Minim Overbag

Used in combination with your lightweight Minim bag to boost its warmth by 23°C. A roomy stand-alone bag in its own right too.
Typical Operating Temperature
Guideline minimum temperature. Sleeping Bag TOT: you should get a night’s sleep, under normal circumstances. Clothing TOT: you should feel warm enough, assuming low/moderate activity. Sleep System TOT: relates to full system. For more details, see our Technical Briefing.
-5°C / 23°F
For clothing, weight is for size: M. For sleeping bags, weight changes with selected length/width. N.B. there may be some variation in the weights of finished products.
780g / 28oz
Minim Overbag

Using the Overbag + Minim has been a revelation. The two bags interact very well, there is no sensation of multiple layers.
Peter McFarlane, a.k.a Petesy, using PHD Overbag with a PHD Ultra.



  • Overbag to boost warmth of main bag. Or wide stand-alone bag
  • Cut wide enough to accommodate an Ultra K, Minimus or Minim 400
  • Exceptional 900 fillpower European Goose Down
  • Lightweight M1 outer fabric
  • Superlight MX inner fabric
  • Box-wall construction for max loft
  • Hood draws up close around head
  • Packed size: 17cm x 28 cm*
  • Footpiece: Ovoid shape to fit naturally to feet & avoid pressure; multibox section covers whole foot area
  • Straight-wall baffles for lightness
  • Stuff-sac & mesh storage bag supplied
  • Colour: Red
  • Set options:
    • Water-resistant Drishell outer fabric
    • Long or Short zip (protected by single draft tube)
    • Slim, Wide and Extra Wide widths†
    • Short, Long, and Extra Long lengths†

*Please note: we make our stuff sacs big enough to allow fairly easy stuffing rather than reducing the bag to the tightest minimum.

†Please note: For all length and width options we change the amount of downfill to keep the warmth (TOT) the same.


Get year-round performance from your Ultralight bag!

We often get asked by marathon and lightweight enthusiasts about doubling up our Ultralight bags for winter use, like putting a Minimus inside a Minim 400. With the standard bags it is not a good idea - the outer bag would not be wide enough to let the inner expand and you would lose a lot of insulation. Hence the Overbag.

The Typical Operating Temperature (TOT) of the Overbag used on its own is -5C (23F) (the same as our Minim 400 bag). Used in combination with another bag it will give a lift of 23C (41F). For example:


Example Combinations Combined TOT
Filler Bag + Overbag = -8C (17.6F)
Minim Ultra K Bag + Overbag = -15C (5F)
Minimus Bag + Overbag = -18C (0F)
Minim 400 Bag + Overbag = -28C (-18F)


At the same time you will have two independent bags for warmer conditions: your Minimus or Ultra K for above zero and your Overbag for a few degrees below.

The versatility and the economies of combining bags need no explanation.

The Overbag offers a great opportunity to use your lightweight gear all year.

Main photo shows Overbag in red Drishell with a Minim 400 in blue Drishell inside (Minim sold separately).

Lightweight M1 fabric (weight: 39 gsm)

Lightweight silky microfibre. This close-weave 20 denier fabric is fully downproof, but also light and flexible enough to allow the down full loft. A reliable performer that has been the basis for much of our lightweight gear for some time.

Superlight MX fabric (weight: 32 gsm)

A mini-ripstop nylon with excellent tear strength, MX is the pick of the superfine 15 denier downproof materials. We have tested lighter fabrics, but most have had significant drawbacks, while our confidence in MX is based on several years of extensive use in both our ultralight and our high mountain gear.

Sleeping bag zips

  • No zip: The standard design on our lightest bags with open hoods. The simplest/lightest system which is a must for adventure racers. Up to 140gm (5oz) lighter than a full zip with draft tube.
  • Full zips: Full zip bags ventilate well, so they can be used over a wider range of temperatures.
  • Short zips: Short zips are lighter and pack smaller than full zips. A short zip & draft tube is up to 85gm (3oz) lighter than the full version.
  • Our full briefing on sleeping bag zips.

900 Fillpower Down

European goose down of very high quality. A truly excellent down with large clusters, consistent quality and lively long-term performance. More on our down insulation.


This bag has an insulating straight wall baffle system throughout (no straight-through stitching). Straight wall is the lightest of all baffle sytems. In cross section it looks like this:

More on sleeping bag construction.

"The fit is very good, no crushing of the inner bag ... and the loft is very good ... The fabrics are all excellent, the Drishell used on the Overbag outer is very good indeed. Water resistant enough to cope with spills, drips and a user daft enough to keep dragging snow into the tent ... the Overbag + Minim has been a revelation. Warm enough for me to abandon all clothing bar my coating of 190 weight merino, and although slim cut, I don't feel restricted in it. The two bags interact very well, there is no sensation of multiple layers ... The two bags feel like one, but it's somehow cosier. I dare say it's one of those things that you have to try, but I have to say I have been warm, comfortable even delighted using these bags ... I think it's good to look at the two bags as a system and as individual bits of kit. That way it does kinda cover the whole year, does that mean it's all you need?"
Peter McFarlane, a.k.a Petesy, using PHD Overbag with a PHD Ultra.

"Just back from an 18 day trek in the region around Everest. I knew the conditions were going to be pretty cold, camping for quite a few nights at around 5000m - night temperatures fell well below minus 15c. Just before I left I purchased the synthetic Overbag bag to go with my Minim 400. The combination worked a treat and - with my Ultra down vest - I never once felt cold during the long nights - even without the hood done up fully. Everything else froze - condensation from my breath turned to ice on the inside of the tent! I was the only one to have such luxury and my trekking companions were just a little envious of my warm glow!"
Gordon G.

""I 'bivvied' in the snow on the fell above my house. Inside a bivvy bag I was as 'snug as a bug' in the Overbag and Filler. So much so that I slept until 8am. The temperature dropped to about -6°C."

"No one I know goes hiking in a big thick woolly jumper, so applying the layering principle to sleeping bags makes as much sense as it does for clothing. This past summer I used the PHD Minimus and PHD Down Overbag.

Immediately the benefits became obvious. Two smaller bags took up about the same space as my old bag, but were considerably easier to pack into dry bags each morning. Stowing them in separate compartments reduced the chance of them both getting wet and made packing the kayak much easier with less wasted space.

On occasions when conditions were [warmer] the inner bag was more than sufficient on its own – at these times I didn't even unpack the second bag from the kayak, thus saving time and energy the following day. Being able to slide either the inner bag down round your legs or the outer bag off made regulating your temperature easy on warmer nights.

It's now so obvious - I can’t believe it's taken me 30 years to apply this layering principle to my sleeping system."
Martin Rickard,

"I have a long-held belief in the 'layering principle' extending into sleeping bags. PHD's bags suit a multitude of adventure activity situations including:

  • Expedition sea kayaking
  • Himalayan style trekking where you travel through a wide range of temperature zones
  • Cycle touring where there is a similar packing issue to sea kayaking and potential for travelling through temperature zones
  • Plus, anyone who needs to use their sleeping bag across seasons. E.g. Just 'layer up' to convert your summer bag into a 'winter warmer'
During recent sea kayak expeditions in Greenland, my PHD Overbag, Filler bags were tested in temperatures ranging from just above freezing to as low as -10°C. It is a pleasure, when you know the temperature is dropping, just to slip into another bag and double the warmth factor"
Sam Cook


Works well with
From £384.00 465g +5℃
Minimalist design cuts weight, but not warmth. For lightweight camping, mountain...
From £457.00 670g -5℃
Minimalist design cuts weight, but not warmth. For lightweight camping, mountain...
From £666.00 620g -20℃
A lightweight mountaineers' and trekkers' Jacket for the 6000m Himalayan peaks,...