Xero Down Suit: K Series














Fantastic ... felt toasty at -25C even when the wind picked up. It was a pleasure to live in them day and night.
Olga Kotova - using Xero down suit on Everest.
Features
- PHD 'K Series' Product: Ultimate warmth / weight performance
- Unique 1000 fillpower European Goose down
- Water-resistant Ultrashell outer: our lightest-ever proofed fabric
- Superlight 10X inner: our lightest-ever downproof fabric
- Box-wall construction for maximum loft
- Differential Cut allowing full down loft
- New: Now available in custom sizes: specify body width, body length, arm length and leg length independently.*****
- Tough HS2 fabric reinforcement at knees/bum & sleeve/shoulder
- Front closure: 2 way zip covered by double baffle and Velcro
- Short side zips (ankle to knee)
- 6 pockets:
- 2 cargo pockets
- 2 handwarmer pockets
- 2 inner water-bottle pockets with elasticated entry
- Hood:
- large size with rear volume reducer
- elastic face cord with cord ends channels
- sewn on with adjustable front velcro closure
- Arms and Knees articulated
- Rainbow seat zip for toilet access
- Elasticated waist and elasticated inner back for snug fit
- Warm knitted cuffs
- Internal braces - adjustable for varied clothing - removable
- Reflector tape on pockets and back of hood for night searches
- Beard flap
- Mitt attachments at chest
- Stuff sac
- Pack size: 25 x 44cm*
- Options:
- Detachable hood (zip-on/stud-on)
- Velcro patches on chest to attach mitts for quick in-out usage
- Under and Up zip as alternative for toilet access
* Please note: we make our stuff sacs big enough to allow fairly easy stuffing rather than reducing clothing to the tightest minimum.
Description
This K Series product has been created for one single reason, to take warmth-for-weight performance to the limit of what's possible. Unique 1000 down, super-light materials, and specific design features mean that the word Ultralight now applies to this wide range of gear that will take you to the Poles as well as on a Sahara Marathon. More on the K Series...
An even lighter version of our Xero Down Suit. The ideal lightweight suit for today's fast ascents. It has seen many summits on Everest and the other 8000m giants. The Xero suit has full expedition specifications, with box-wall construction, expedition-style pockets inside and out, a voluminous hood and many other features. Designed to provide incredible weather protection on rapid high-altitude ascents or lightweight polar expeditions.
Technical
Toilet Access on Suits
- Under & Up zip: The central front zip on the suit runs from the collar, down the front of the body, past the groin and then under and up to waist level at the back. A two-way zip allows access at any place.
- Rainbow Seat zip: A rainbow / semicircle zip is sewn in across the backside. A two-way zip allows access and creates a drop down flap.
Ultrashell (weight: 40gsm)
The lightest of PHD's coated materials. This ripstop nylon provides complete wind block and good water resistance at minimal weight. Ultrashell gives an excellent upgrade to performance with very little weight penalty.
Ultralight 10X fabric (weight: 26 gsm)

10X, PHD's First 10 Denier Fabric. 9,000 metres of the yarn used to weave 10X weighs just 10g, that's about the same as a £1 coin! For all its thinness 10X is amazingly downproof and with reasonable care will go on giving you good service for years.
1000 Fillpower Down

This rarest of all downs we reserve for the K Series. European goose down of unique quality. 1000 provides the highest warmth-for-weight performance possible from down. More on our down insulation.
Waterproof HS2 outer fabric (weight: 88 gsm)

HS2 is PHD's high-spec 2-layer ripstop for waterproof outers on our down. It is light enough to be the optional taped shell on our sleeping bags and tough enough for expedition use in our Omega clothing. HS2 is completely waterproof (when the seams are taped) and offers excellent breathability.
Sizing
Standard Sizing
The PHD Sizing Chart below is based on measurements without clothing, exactly the way you would buy a shirt, a sweater or a pair of trousers. A 42" (107cm) chest means that your bare chest uninflated measures 42". Inside Arm is measured from armpit to wrist-bone. Inside leg is measured from crotch to ankle-bone.
Size | Height | Chest | Waist | Inside arm | Inside leg |
---|---|---|---|---|---|
XS | 155-163cm (5'1"–5'4") |
86cm (34") |
71cm (28") |
46cm (18") |
69cm (27") |
S | 164-170cm (5'5"–5'7") |
91cm (36") |
76cm (30") |
48cm (19") |
72cm (28.5") |
M | 171-178cm (5'7"–5'10") |
99cm (39") |
84cm (33") |
51cm (20") |
76cm (30") |
L | 179-186cm (5'10"–6'1") |
107cm (42") |
91cm (36") |
53cm (21") |
80cm (31.5") |
XL | 187-193cm (6'2"–6'4") |
114cm (45") |
99cm (39") |
56cm (22") |
84cm (33") |
Custom Sizing
Once you've selected a Body Width you can choose Body Length, Arm Length, and Inside Leg up to two sizes bigger or smaller. For example, a suit with a medium (M) Body Width can be XS, S, M, L, or XL in Body Length; XS, S, M, L, or XL in Arm Length; and XS, S, M, L, or XL in Inside Leg. If you have any questions about your size, please contact us.
Body Width. Use the chart below to find your Body Width. Measure yourself without clothes, relaxed with an uninflated chest.
Body Width | Chest circumference | Waist circumference |
---|---|---|
XS | 86cm (34") | 71cm (28") |
S | 91cm (36") | 76cm (30") |
M | 99cm (39") | 84cm (33") |
L | 107cm (42") | 91cm (36") |
XL | 114cm (45") | 99cm (39") |
Body Length -- can be two sizes up or down from Body Width. Use the chart below to find your Body Length size. Measure your height without shoes:
Body Length Size |
Your height in cm | Your height in inches |
---|---|---|
XXXS | 139 - 144cm | 4'5" - 4'8" |
XXS | 145 - 154cm | 4'9" - 5' |
XS | 155 - 163cm | 5'1" - 5'4" |
S | 164 - 170cm | 5'5" - 5'7" |
M | 171 - 178cm | 5'7" - 5'10" |
L | 179 - 186cm | 5'10" - 6'1" |
XL | 187 - 193cm | 6'2" - 6'4" |
XXL | 194 - 201cm | 6'4" - 6'7" |
XXXL | 202 - 209cm | 6'8" - 6'10" |
Inside Arm -- can be two sizes up or down from Body Width. Inside Arm is measured from armpit to wrist-bone without clothes. When you measure your inside arm let your arm hang loosely by your side. Don't extend it horizontally.
Inside Arm | cm | Inches |
---|---|---|
XXXS | 41cm | 16" |
XXS | 43cm | 17" |
XS | 46cm | 18" |
S | 48cm | 19" |
M | 51cm | 20" |
L | 53cm | 21" |
XL | 56cm | 22" |
XXL | 58cm | 23" |
XXXL | 61cm | 24" |
Inside Leg. Use the chart below to find your Inside Leg size. Measure yourself without clothes from crotch to ankle bone.
Inside Leg size | Inside Leg length |
---|---|
XXXS | 61cm (24") |
XXS | 65cm (25.5") |
XS | 69cm (27") |
S | 72cm (28.5") |
M | 76cm (30") |
L | 80cm (31.5") |
XL | 84cm (33") |
XXL | 88cm (34.5") |
XXXL | 91cm (36") |
N.B. PHD clothing is unisex.
Notes:
- Down suits are sized to fit over thermal underwear and fleece.
- Shell Suits: D-type suits will fit over down clothing of the same named size: F-type suits will only fit over thermals and fleece.
- The arms of our suit are designed to be long enough to keep your wrists warm when your arms are extended horizontally (when using trekking poles, for example) or when you are reaching above yourself (when climbing, for example). In this respect the arm lengths of our suits differ from street/fashion jackets.

Reviews
"Fantastic ... felt toasty at -25C even when the wind picked up. It was a pleasure to live in them day and night."
— Olga Kotova - using Xero down suit on Everest. Olga was the first woman from a Baltic State to summit Everest.
"Wow, just wow. This is way better than anything Batman or Superman puts on. Truly impressed with the engineered finished product".
— Chase Hinckley.
"I ordered a Xero down suit ... off you guys middle of
last year. I used [it] on Cho Oyu and [it] worked fantastically ... I did put the gear through a thorough test and am totally happy with the way [it] performed."
— Ben Kane, Guide
"Just a quick note to let you know that ALL 5 members of our team reached the
Summit of Cho Oyo (8201m). I wore my Xero Down suit with 800 fill on
the summit day and [it was] fantastic, the temp was -25C on the summit with
a brisk 20-25 knot westerly wind, and I
remained cosy warm for the 13 hours it took to get from camp 2 (7200m) to
the summit and back down to camp 2.
Thanks for the great gear."
— 'Lanx', UK Reserve Forces Seven Summits team.
"One of the most practical one-piece 8,000-metre down suits available. With six pockets and internal braces reinforced in key wear areas ... Designed by the man who produced the legendary Annapurna duvet jacket, the wind and snowproof Xero sports the same box wall construction found in top flight sleeping bags. Fitted with articulated knees and arms for ease of movement."
— Geographical Magazine.
Features
- PHD 'K Series' Product: Ultimate warmth / weight performance
- Unique 1000 fillpower European Goose down
- Water-resistant Ultrashell outer: our lightest-ever proofed fabric
- Superlight 10X inner: our lightest-ever downproof fabric
- Box-wall construction for maximum loft
- Differential Cut allowing full down loft
- New: Now available in custom sizes: specify body width, body length, arm length and leg length independently.*****
- Tough HS2 fabric reinforcement at knees/bum & sleeve/shoulder
- Front closure: 2 way zip covered by double baffle and Velcro
- Short side zips (ankle to knee)
- 6 pockets:
- 2 cargo pockets
- 2 handwarmer pockets
- 2 inner water-bottle pockets with elasticated entry
- Hood:
- large size with rear volume reducer
- elastic face cord with cord ends channels
- sewn on with adjustable front velcro closure
- Arms and Knees articulated
- Rainbow seat zip for toilet access
- Elasticated waist and elasticated inner back for snug fit
- Warm knitted cuffs
- Internal braces - adjustable for varied clothing - removable
- Reflector tape on pockets and back of hood for night searches
- Beard flap
- Mitt attachments at chest
- Stuff sac
- Pack size: 25 x 44cm*
- Options:
- Detachable hood (zip-on/stud-on)
- Velcro patches on chest to attach mitts for quick in-out usage
- Under and Up zip as alternative for toilet access
* Please note: we make our stuff sacs big enough to allow fairly easy stuffing rather than reducing clothing to the tightest minimum.
Description
This K Series product has been created for one single reason, to take warmth-for-weight performance to the limit of what's possible. Unique 1000 down, super-light materials, and specific design features mean that the word Ultralight now applies to this wide range of gear that will take you to the Poles as well as on a Sahara Marathon. More on the K Series...
An even lighter version of our Xero Down Suit. The ideal lightweight suit for today's fast ascents. It has seen many summits on Everest and the other 8000m giants. The Xero suit has full expedition specifications, with box-wall construction, expedition-style pockets inside and out, a voluminous hood and many other features. Designed to provide incredible weather protection on rapid high-altitude ascents or lightweight polar expeditions.
Technical
Toilet Access on Suits
- Under & Up zip: The central front zip on the suit runs from the collar, down the front of the body, past the groin and then under and up to waist level at the back. A two-way zip allows access at any place.
- Rainbow Seat zip: A rainbow / semicircle zip is sewn in across the backside. A two-way zip allows access and creates a drop down flap.
Ultrashell (weight: 40gsm)
The lightest of PHD's coated materials. This ripstop nylon provides complete wind block and good water resistance at minimal weight. Ultrashell gives an excellent upgrade to performance with very little weight penalty.
Ultralight 10X fabric (weight: 26 gsm)

10X, PHD's First 10 Denier Fabric. 9,000 metres of the yarn used to weave 10X weighs just 10g, that's about the same as a £1 coin! For all its thinness 10X is amazingly downproof and with reasonable care will go on giving you good service for years.
1000 Fillpower Down

This rarest of all downs we reserve for the K Series. European goose down of unique quality. 1000 provides the highest warmth-for-weight performance possible from down. More on our down insulation.
Waterproof HS2 outer fabric (weight: 88 gsm)

HS2 is PHD's high-spec 2-layer ripstop for waterproof outers on our down. It is light enough to be the optional taped shell on our sleeping bags and tough enough for expedition use in our Omega clothing. HS2 is completely waterproof (when the seams are taped) and offers excellent breathability.
Sizing
Standard Sizing
The PHD Sizing Chart below is based on measurements without clothing, exactly the way you would buy a shirt, a sweater or a pair of trousers. A 42" (107cm) chest means that your bare chest uninflated measures 42". Inside Arm is measured from armpit to wrist-bone. Inside leg is measured from crotch to ankle-bone.
Size | Height | Chest | Waist | Inside arm | Inside leg |
---|---|---|---|---|---|
XS | 155-163cm (5'1"–5'4") |
86cm (34") |
71cm (28") |
46cm (18") |
69cm (27") |
S | 164-170cm (5'5"–5'7") |
91cm (36") |
76cm (30") |
48cm (19") |
72cm (28.5") |
M | 171-178cm (5'7"–5'10") |
99cm (39") |
84cm (33") |
51cm (20") |
76cm (30") |
L | 179-186cm (5'10"–6'1") |
107cm (42") |
91cm (36") |
53cm (21") |
80cm (31.5") |
XL | 187-193cm (6'2"–6'4") |
114cm (45") |
99cm (39") |
56cm (22") |
84cm (33") |
Custom Sizing
Once you've selected a Body Width you can choose Body Length, Arm Length, and Inside Leg up to two sizes bigger or smaller. For example, a suit with a medium (M) Body Width can be XS, S, M, L, or XL in Body Length; XS, S, M, L, or XL in Arm Length; and XS, S, M, L, or XL in Inside Leg. If you have any questions about your size, please contact us.
Body Width. Use the chart below to find your Body Width. Measure yourself without clothes, relaxed with an uninflated chest.
Body Width | Chest circumference | Waist circumference |
---|---|---|
XS | 86cm (34") | 71cm (28") |
S | 91cm (36") | 76cm (30") |
M | 99cm (39") | 84cm (33") |
L | 107cm (42") | 91cm (36") |
XL | 114cm (45") | 99cm (39") |
Body Length -- can be two sizes up or down from Body Width. Use the chart below to find your Body Length size. Measure your height without shoes:
Body Length Size |
Your height in cm | Your height in inches |
---|---|---|
XXXS | 139 - 144cm | 4'5" - 4'8" |
XXS | 145 - 154cm | 4'9" - 5' |
XS | 155 - 163cm | 5'1" - 5'4" |
S | 164 - 170cm | 5'5" - 5'7" |
M | 171 - 178cm | 5'7" - 5'10" |
L | 179 - 186cm | 5'10" - 6'1" |
XL | 187 - 193cm | 6'2" - 6'4" |
XXL | 194 - 201cm | 6'4" - 6'7" |
XXXL | 202 - 209cm | 6'8" - 6'10" |
Inside Arm -- can be two sizes up or down from Body Width. Inside Arm is measured from armpit to wrist-bone without clothes. When you measure your inside arm let your arm hang loosely by your side. Don't extend it horizontally.
Inside Arm | cm | Inches |
---|---|---|
XXXS | 41cm | 16" |
XXS | 43cm | 17" |
XS | 46cm | 18" |
S | 48cm | 19" |
M | 51cm | 20" |
L | 53cm | 21" |
XL | 56cm | 22" |
XXL | 58cm | 23" |
XXXL | 61cm | 24" |
Inside Leg. Use the chart below to find your Inside Leg size. Measure yourself without clothes from crotch to ankle bone.
Inside Leg size | Inside Leg length |
---|---|
XXXS | 61cm (24") |
XXS | 65cm (25.5") |
XS | 69cm (27") |
S | 72cm (28.5") |
M | 76cm (30") |
L | 80cm (31.5") |
XL | 84cm (33") |
XXL | 88cm (34.5") |
XXXL | 91cm (36") |
N.B. PHD clothing is unisex.
Notes:
- Down suits are sized to fit over thermal underwear and fleece.
- Shell Suits: D-type suits will fit over down clothing of the same named size: F-type suits will only fit over thermals and fleece.
- The arms of our suit are designed to be long enough to keep your wrists warm when your arms are extended horizontally (when using trekking poles, for example) or when you are reaching above yourself (when climbing, for example). In this respect the arm lengths of our suits differ from street/fashion jackets.

Reviews
"Fantastic ... felt toasty at -25C even when the wind picked up. It was a pleasure to live in them day and night."
— Olga Kotova - using Xero down suit on Everest. Olga was the first woman from a Baltic State to summit Everest.
"Wow, just wow. This is way better than anything Batman or Superman puts on. Truly impressed with the engineered finished product".
— Chase Hinckley.
"I ordered a Xero down suit ... off you guys middle of
last year. I used [it] on Cho Oyu and [it] worked fantastically ... I did put the gear through a thorough test and am totally happy with the way [it] performed."
— Ben Kane, Guide
"Just a quick note to let you know that ALL 5 members of our team reached the
Summit of Cho Oyo (8201m). I wore my Xero Down suit with 800 fill on
the summit day and [it was] fantastic, the temp was -25C on the summit with
a brisk 20-25 knot westerly wind, and I
remained cosy warm for the 13 hours it took to get from camp 2 (7200m) to
the summit and back down to camp 2.
Thanks for the great gear."
— 'Lanx', UK Reserve Forces Seven Summits team.
"One of the most practical one-piece 8,000-metre down suits available. With six pockets and internal braces reinforced in key wear areas ... Designed by the man who produced the legendary Annapurna duvet jacket, the wind and snowproof Xero sports the same box wall construction found in top flight sleeping bags. Fitted with articulated knees and arms for ease of movement."
— Geographical Magazine.