How to Choose an Alpkit Insulated Jacket

How to Choose an Alpkit Insulated Jacket

By Alex Guerrero

If you don’t know your Filoment from your Fantom, then fear not. We’ve put together a brief AlpDictionary of our nine insulating outer layers so you can find what you need to help you conquer the cold and Win Winter. And if words like fill power, PrimaLoft® and micro-baffle all sound a bit like gibberish, then you might need our ultimate guide to down jackets and synthetic insulation.

A Brief Overview

  1. A Quick Comparison
  2. Sierra PrimaLoft® Vest
  3. 0Hiro PrimaLoft® Jacket
  4. Talini PrimaLoft® Jacket
  5. Katabatic PrimaLoft® Jacket
  6. Filoment Micro-Baffle Down Vest
  7. Filoment Micro-Baffle Down Hoody
  8. Fantom Down Jacket
  9. Jura Smock

A Quick Comparison


Weight: men’s M / women’s 12 (g)




273 / 246

100% recycled insulation

60gsm PrimaLoft® Gold P.U.R.E


690 / 630

Retains 85% of insulating value when wet

PrimaLoft® Silver Hi-Loft Ultra (Body: 120gsm / Arms & Hood: 80gsm)


390 / 340

C0 PFC-free DWR coating

PrimaLoft® Silver ThermoPlume® with Cross Core Technology


455 / 400

45% post-consumer recycled materials

PrimaLoft® Gold Active Eco, 60 gsm

Filoment Vest

240 / 210

PFC-free DWR coating

630 FP down

Filoment Hoody

405 / 358

PFC-free DWR coating

630 FP down


642 / 518

PFC-free C0

650 FP down


820 / 680

PFC-free DWR

100% recycled polyester fleece


Sierra vest

What is it: PrimaLoft® Gold gilet with breathable fleece panels. Full zip for the “am I too hot? Or am I too cold?” days. With zipped chest pocket and two zipped hand pockets.

Good for: working hard on the hills, crags and trails. The Sierra leaves your arms free to reach for drops or holds, whilst keeping your warmth where you need it most.

Sustainability:  The insulation is 100% recycled polyester and the fleece panels are 92% recycled polyester, coming from sources like old plastic bottles. The nylon fabric is also 100% recycled and made using fabric scraps and leftover materials from nylon manufacturing.

Designer’s notes: "We were very excited to be able to make one of the first garments on the market using PrimaLoft® P.U.R.E.™ technology. This technology goes beyond using recycled materials, reducing carbon emissions throughout the whole production process – and all without sacrificing any performance!"


man wearing 0hiro

What is it: A superhero below 0°C and master of moist maritime winters – the perfect UK winter jacket; our warmest synthetic layer, using lots of lofted PrimaLoft® fill and a bomber outer fabric. It retains over 85% of its insulating ability when wet! It’s got a helmet compatible hood, a full zip and four pockets for stashing snacks (…or hats and gloves).

Good for: Unbeatable damp-resistant warmth; an outer layer for low intensity activities with a risk of drizzle or sleet; burrowing through snowy gullies in wind-blasted Scottish winter.

Sustainability: 100% recycled polyester liner and 70% recycled PrimaLoft® insulation. Nylon 6,6 outer to last for seasons and PrimaLoft® Hi-loft Ultra survives repeated compressions for longer. It also uses a completely PFC-free DWR treatment so we can say “see ya later” to potentially harmful nasty chemicals.

Designer's notes: "The 0Hiro is a real get-out-of-jail free card when unexpected weather hits: we've added a 5K/5K waterproof membrane to the outer to give you extra time to get off the hill warm and dry."


Man wearing Talini

What is it: A passport to ultimate worry-free warmth; light and compressible jacket using innovative down-imitation fill from PrimaLoft®; a full zip windproof outer jacket or a toasty mid layer. The lightweight, hoodless Talini has got zipped handwarmer pockets and a zipped chest pocket.

Good for: Packable rest-stop warmth throughout the year; an outer layer for cold and windy hill walks; an ultra-warm mid layer when the weather gets really nasty; damp British camping!

Sustainability: The outer fabric is treated with a C0 Durable Water Repellent finish, which is completely PFC-free – no nasty chemicals

Designer's notes: "PrimaLoft® ThermoPlume is the closest you can get to down levels of performance: the synthetic fill is equivalent to around 600 FP and performs better in the wet than even hydrophobic down."


man wearing katabatic

What is it: The jacket you’ll never take off; toasty PrimaLoft® Gold Active fill and air-permeable fabrics for maximum mid layer breathability plus wind-resistance for outer use – two jackets in one! The Katabatic has a simple insulated hood, an adjustable drawcord hem and 3 zipped pockets.

Good for: Working up a sweat, slogging up cold and windy hillsides; under a shell when the weather gets spicy; unrestrictive warmth for scrambling; high effort activities in changing conditions.

Sustainability: PrimaLoft® Gold Active uses 45% post-consumer recycled content to increase its sustainability without compromising performance.

Designer's notes: "If you own just one synthetic insulated jacket, this should be it. No more boil-in-the-bag feeling when you’ve left it on too long: the breathable fabric and insulation work as hard as you do."

Filoment Vest

 woman wearing filoment vest

What is it: Light and packable 630FP fill power down gilet using 100% recycled fabric and fill. The full zip, 3-pocket Filoment keeps your core insulated when weight and freedom of movement are your top priorities.

Good for: Layering up and packing down. Stuff the Filoment in your rucksack for warmth and freedom of movement on the go.

Sustainability: We’re now using PFC-free DWR treatments. They’re non-toxic and don’t build up in the environment, so we’re pretty pleased about that. The Filoment also uses 100% recycled nylon fabric and RCS 100-certified recycled down!

Designer’s notes: “Don’t neglect the importance of your core when you’re trying to keep your extremities warm. Design Tech Gabe always goes for a Filoment vest first when trying to save his freezing hands when winter climbing.”

Filoment Hoody

Man walking with Filoment hoody

What is it: The feather-lite champion of packability; a micro-baffle down jacket with a ridiculously small pack size for its warmth; a low-profile outer jacket or sub-zero mid layer.

Good for: Fast and light mountain raids; packing away into backpacks and bikepacking bags for cold evenings in the tent/bothy; low-bulk warmth for UK winter/alpine summer scrambles.

Sustainability: Downtek PFC-free Hydrophobic down and a PFC free DWR-treated outer fabric. Responsibly sourced (RDS-approved) Down.

Designer's notes: "There's a reason why you see so many people in micro-baffle down jackets: they're the holy grail of warmth, packability and ultralight weight – they really are hard to beat for versatility."


Climber wearing Fantom down jacket

What is it: The cold conqueror; the warmest jacket in our family, with a lightweight ripstop outer to pack neatly into rucksacks and mountaineering-ready features for altitude adventures. It’s got chunky baffles to keep you snug subzero, a helmet compatible hood and a longer cut to keep your bum warm! Despite its next-level warmth, it’s got a great warmth-to-weight ratio and is highly compressible.

Good for: Instant warmth for stationary activities or moving at altitude in extreme cold; belaying in fine conditions; camping on cold, clear nights; between ‘send’ attempts in grit season.

Sustainability: Downtek PFC-free Hydrophobic down and a PFC free DWR-treated outer fabric. Responsibly sourced (RDS-approved) down.

Designer's notes: "Probably the warmest jacket you’ll ever need - you may find yourself wishing it was colder just so you can wear it! We're really proud of little touches like the cosy tricot-lined collar and pockets."


Photographer wearing Jura smock

What is it: Hardwearing all-in-one layer with a weatherproof outer and thick fleece insulation. A true, throw-on classic with huge map pocket and fleecy hood.

Good for: Throwing on and leaving on, from crisp Autumn walks to cold, damp and downright nasty winter climbs.

Sustainability: The fleece lining of the Jura Mountain Smock is made using 100% recycled polyester from post-consumer recycled content. And the outer fabric is treated with a PFC-free durable water repellent to avoid the use of potentially harmful man-made chemicals.

Designer’s notes: "There’s something satisfying about walking out into the teeth of a gale wearing a jacket that you can leave on all day without having to constantly change layers. That’s why we’ve included huge venting zips from hem to elbow so you can dump heat rapidly, and a hood that you can really bury your face in when the chill sets in. It’s the simplicity of just being able to get on with the job at hand that makes layers like this the choice of Mountain Rescue teams across the country." - Ronnie, Design Manager

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