Beta Belay Jacket

Our lightest Primaloft-insulated belay jacket for unfriendly wild & damp conditions. Designed for “layering up” for the long walk-ins, tough climbing days on classic mixed mountain routes and technical steep water-ice. Also available in custom sizes.
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.
0°C / 32°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.
530g / 19oz
Beta Belay Jacket


  • Outer fabric: Waterproof / Breathable Dri-LX outer fabric* (with taped shoulder seams)
  • Inner Fabric: Breathable ripstop superlight MX
  • Primaloft Gold® synthetic insulation (60g/m weight in body and sleeves)
  • Shoulder seams taped
  • Front closure - 2 way YKK Aquaguard water-resistant zip with bottom locking stud
  • 3 insulated pockets:
    • 2 zipped waist level pockets
    • 1 zipped chest pocket
  • Integral hood with wired peak, sized for a modern climber's helmet:
    • Adjustable front cord with cord ends tethered inside the hood
    • Wired peak
    • Volume reducer on the back of the hood
  • Reflector tape on front and back for night location
  • Clip loop to secure jacket at change-overs
  • Double exit adjustable hem cord
  • The Primaloft filling is edge stitched only to allow maximum loft
  • Cuffs; simple Velcro closure, to go over or under gloves
  • Stuff sac
  • Pack size: 13 x 21cm**

*Please note: although the outer fabric is waterproof, only the shoulder stitch lines are taped. So, although the outer will shed a lot of rain and snow, in a heavy downpour water can penetrate the stitching. However, the Primaloft Gold® insulation retains much of its insulation if wet. As always in the mountains, if there is a possibility of prolonged rain, carry full specification waterproofs.

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


Also available in custom sizes. We make clothing to order, so if you’re not a standard size we can make it to fit. To order a non-standard custom size, select the Custom Sizing tab, choose your body width, and then the body/arm lengths, shorter or longer, that work for you. A custom size takes us a little longer (typically two weeks longer) to make and, because it’s personalized, it’s non-returnable and our customer loyalty scheme can’t be applied.

The lightest synthetic-filled belay jacket that we make, the Beta has been designed for use when layering to manage and prevent both overheating and becoming cold. By combining it with an insulated layer, such as the Primaloft Sigma or Gamma Vests, the ideal comfort spots can be achieved for the “walk in”, when climbing, and when belaying. Our lightweight Dri-LX fabric and the 60gr/m2 Primaloft synthetic filling have been used to achieve a super lightweight and packable jacket

Part of PHD’s collection of synthetic filled Belay Jackets (the Beta, Epsilon, Alpha and Zeta, with TOT* ratings of 0°C, -5°C /-10°C /-20°C respectively), these technical insulating tops are perfectly adapted to wild, wet, unforgiving conditions: typical Scottish winter, essentially. It doesn’t end there though: demanding routes in demanding conditions – whether on steep water ice, big mountain faces or classic mixed test-pieces – are where these jackets belong, and those conditions will be familiar to climbers throughout Scandinavia, the Alps, the Arctic and Patagonia.

If you choose to swap one jacket between two of you as you change over at belays, you’ll find the cut is roomy enough to fit over your outer layers. If you’re keeping it for yourself though and climbing in it all day, the fit is nevertheless trim and efficient: ideal for wearing under your harness.

Freedom of movement is essential for a climber’s jacket, and so of course is protection from the elements. The climber-specific fit, lightweight waterproof fabric (with taped shoulder seams), grown on hood, full length water-resistant zip, extra body length, and pocket locations make for a solid, dependable jacket which allows you to just get on with the task at hand. These features are repeated throughout the collection, and with different levels of warmth to choose from, these belay jackets prepare you for a vast range of winter climbing adventures.

The jackets in the collection share the same feature list but have different thickness of Primaloft insulation:


Weight of
Primaloft Gold

Beta Belay 60g/m2 0°C
Epsilon Belay 100g/m2 -5°C
Alpha Belay 133g/m2 -10°C
Zeta Belay 200g/m2 -20°C


In our experience Primaloft Gold® absorbs water much more slowly than other waddings, a marked advantage in wet-cold conditions. Effectively, if you can retain warm air in the insulation rather than replacing it with cold water, the garment will stay much warmer.

Please note: this jacket is designed and sized to be worn over top / outer layers. It provides additional warmth on cold belays and can be swapped between climbers at pitch change-overs. If you want a trimmer more athletic fit select the next size down.

*TOT: Typical Operating Temperature

Dri-LX (weight: 64 gsm)

At just 64gsm, Dri-LX is our lightest 2-layer breathable waterproof rip-stop nylon fabric. Its remarkably low weight not only makes for a lighter load, but also reduces pack size. Its excellent waterproofing qualities are in part due to how it can be taped at the seams to create a waterproof shell for sleeping bags and clothing.

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.

Primaloft Gold®

Primaloft Gold® is the ideal microfibre insulation. Ultrafine fibres produce an insulating core that is incredibly soft, lightweight and water resistant. In our experience it absorbs water much more slowly than other waddings, a marked advantage in wet-cold conditions.

The nearest of the synthetics to the feel of down, yet tougher than you would expect. Primaloft Gold® offers the best warmth/weight performance in the Primaloft range

Feedback on a warmer version of this jacket, the Epsilon:

"The Epsilon jackets have fast become a go-to jacket for team members given the light weight, warmth and functionality they offer. As much at home on a winter climb, chilly lunch stop, or even wrapped round a casualty, they have been put to a wide variety of practical recent uses. Another outstanding piece of UK-made PHD kit."
Braemar Mountain Rescue Team, users of our standard Epsilon Jacket.

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