While down insulation grabs the headlines for its warmth to weight ratio, loft and comfort, synthetic insulation’s superior route-proof nature means it will keep working when most down insulated kit has given up and gone home. This is why it’s an essential part of our range and a crucial part in any alpinist’s gear cupboard. Stamping your feet at the belay and windmilling your arms to get the blood following as the snow pours down, this is where synthetics earn their keep. Inside that fabric shell is a layer of insulation made from HD wool, a compound of natural sheep’s wool and PLA (polylactic acid, a plastic made from corn starch or sugar cane). It’s also fully biodegradable, while the wool itself is renewable, fully traceable, ethically produced and sourced from farmers who have signed up to eco schemes to improve biodiversity, soil health, natural irrigation systems and carbon sequestering. Full Specification

PEAQ Synthetic ECO lining that is supremely comfortable next to the skin, highly breathable and fast drying Barklow designed the Ambient collection, and his experience is especially relevant because he was responsible for designing uniforms for Special Operations forces when Polartec Alpha was developed. It was his incorporation of the technology that made the uniforms successful. Then there’s the outer shell fabric which is both lightweight and durable thanks to the Cordura fibres that make up the ripstop thread within it. Stretchy fleece-lined panels then line the sides of the torso and under the arms to add a bit of extra comfort and to aid the overall temperature regulation as well. Lined with 100% recycled PEAQ Synthetic ECO fabric which is supremely comfortable next to the skin, highly breathable and fast drying A few weeks ago, I threw a lightweight hoodie over a synthetic T-shirt and started hiking up a mountain near my home in Bozeman, Montana. Temperatures were in the mid-forties when I set out, and a passing thunderstorm dropped them to the mid-thirties by the time I returned. The storm brought high winds and a brief but intense rain shower. Other than pulling up the hood to keep off the rain, I made no adjustments to my clothing system whatsoever, and I remained dry and comfortable.

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The Photon features a Pertex Microlight 30D outer shell that is durable and also wind and water resistant. Inside there is 133g Primaloft Eco in the body and 100g in the sleeves. Primaloft Eco is a synthetic insulation that is thermally efficient, with superior water resistance, dries faster than down, is breathable and is as warm soft and compressible as down. Insulation: 80g PrimaLoft Gold Active (45% recycled content) / 80g Polartec Alpha (55% recycled content) / shell: 20D stretch ripstop polyamide shell / available in S-XXL. Selected for the 2021/22 Outdoor 100 – Read our full Keela Talus review. BUY NOW: KEELAOUTDOORS.COM The headline material here is OR’s VerticalX Eco SR insulation. This combines Repreve recycled polyester fill with Sorona, a renewable plant-based fabric that is particularly hard-wearing. The result is a highly compressible fill that offers excellent warmth for weight, a soft down-like feel and good performance even when wet.

PrimaLoft ThermoPlume synthetic fill, which mimics the loft and fill power properties of down with the fast drying warmth of traditional PrimaLoft insulation 100% recycledSelected for our Green Gear Guide 2023– Read our full The North Face Thermoball 50/50 review. BUY NOW: BANANAFINGERS.CO.UK