A Warm Synthetic Insulated Jacket

Recent years have seen a move to insulated jackets with increased breathability so they are comfortable when moving even if that’s at the expense of windproofing. This jacket from Mammut is one of the best compromises between wind resistance and breathability I’ve come across. The jacket has a shell made of Pertex Quantum Air, which is more air permeable than other types of Pertex, and a filling of Mammut’s own OTI insulation. Both materials stretch a little so the Rime Flex can be close-fitting and still move with you.

There’s 100 grams per square metre of insulation, which makes the jacket quite warm. The lightest synthetic insulated jackets have 60 gsm filling. This a jacket for really cold weather. It’s too warm for me to walk in unless it’s stormy and the temperature is zero or below. The medium size weighs 445 grams. It just fits me over a base layer. If I wanted to wear it over more layers I’d need a larger size. It would have to be very cold for me to need to do so though. The jacket keeps out all but the strongest coldest winds and is more breathable than many synthetic filled jackets.

The Rime Flex has an adjustable helmet compatible hood. The volume can be easily reduced for non-helmet wear. The hood has a peak but it’s so soft it’s useless. The pockets are excellent. There are two mapsize handwarmer ones set high enough not to be cut off by a hipbelt and two smaller chest ones suitable for GPS, compass or phone. The cuffs are elasticated, the hem has a drawcord with cordlocks either side.