Selected for our Green Gear Guide 2023 – Read our full Outdoor Research Shadow Insulated Hoody review. BUY NOW: OUTDOORRESEARCH.COM Lined with 100% recycled PEAQ Synthetic ECO fabric which is supremely comfortable next to the skin, highly breathable and fast drying PrimaLoft ThermoPlume synthetic fill, which mimics the loft and fill power properties of down with the fast drying warmth of traditional PrimaLoft insulation 100% recycled 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

Synthetic insulation works best when you need it the most. It thrives in bad conditions, where its superior water resistance and real-life durability are most important. We've been working with it for 50 years, and have repeatedly innovated in this area, from the introduction of hollow fill insulations to the use of continuous filament insulations.

Selected for our Green Gear Guide 2023– Read our full The North Face Thermoball 50/50 review. BUY NOW: BANANAFINGERS.CO.UK

We’ve not yet quite mastered a like-for-like synthetic alternative to down – its formation is just too unique – and so there are still some downsides (sorry) to synthetic insulation in comparison to it. That being said, there are also some upsides to using synthetic insulation over down. Insulated with PrimaLoft® ThermoPlume, the hood is designed to be worn comfortably under a climbing helmet With Musto's industry leading BR1, 2 layer waterproof and breathable fabric that is stringently tested to provide excellent protection and comfort in the most persistent downpours PrimaLoft® has been the outdoor industry’s leading synthetic insulation for over a decade. Originally developed for the US military who required an insulation that would work in any conditions and provide the most warmth for its weight, PrimaLoft® soon found its way into the outdoor industry. That PrimaLoft® was patented under the name ‘artificial down’ gives you a good idea of the high standards PrimaLoft® were gunning for.

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. Filled with premium PrimaLoft® ThermoPlume synthetic fill, a special blend of PrimaLoft® proprietary fibres that mimics the loft and fill power properties of down with the fast drying warmth of traditional PrimaLoft® insulation 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.