Mountain Equipment has given its Extreme Light sleeping bag range a big update for spring, producing bags that push the boundaries of the warmth-to-weight ratio.
The Xenith Sleeping Bag collection, which already featured an astonishingly low weight and pack size, has been redesigned using the brand's secret weapon: Plasma 10D fabric. Now they're even lighter than they were before, while still keeping you warm in temperatures as low as -8°C/18°F.
According to the brand, Plasma 10D is "perhaps the strongest superlight nylon fabric available" but has exceptional tear resistance, where durability is often sacrificed when grams are shaved. It's also exceptionally breathable, which is crucial for getting a good night's sleep, and that's why alpinists, thru-hikers and other mountain athletes reportedly love these sleeping bags.
This isn't the first time the brand has used Plasma 10D – it tested it out in the Oreus Hooded Jacket which won an IPSO award in 2023 for its excellent warmth-to-weight ratio, so it's no surprise they're now using it in sleeping bags which need to be light, warm and tough.
The Xenith sleeping bag line comprises three different temperature ratings and harnesses the power of 900 fill power goose down for lightweight and compressible insulation that's easier to pack, plus a PFAS-free DWR.
The Xenith III is the warmest of the bags with a comfort limit rating of -8°C/18°F and it weighs 690g (24oz). That places it as among the very lightest sleeping bags we've tested, with only the Therm-A-Rest Hyperion 20F weighing less. But the other two are even lighter.
The Xenith II is intended for summer expeditions with a comfort limit rating of 3°C/37°F and a weight of only 470g (17oz), while at just 360g (13oz) the Xenith I is cheaper than a lot of waterproof jackets and is brilliant for fastpacking and mountain running expeditions with a comfort limit rating of 5°C/41°F.
If you're still shopping for lightweight bags, we're also big fans of the Rab Neutrino Pro 400 and Alpkit Pipedream 400.
