Mountain Equipment Sleeping Bag Ranges Explained
Posted by Mark Richardson on Jan 22, 2026
Xenith
The predecessors to the Xenith bags were a consistent favourite with our team of climbers and they’ve been used for some of the hardest and most committing alpine climbing of recent years in the Himalaya, Karakoram and Alaska. At the same time they’ve been everywhere from classic ascents in Patagonia, Yosemite and the European Alps to long distance back packing and ski trips where every gram counts.
Now completely re-designed, the Extreme Light Range, comprising the Xenith I, II and III, has been improved in every way, combining the experience from thousands of nights of use with all our design expertise.
Helium Series
Exceptional Performance, Trekking Bag
The Helium series bags achieve high performance ratings using 800 Fill Power down and Mountain Equipment's improved construction techniques.
The shell fabric is highly breathable and has a 'light touch' DWR providing some water resistance making the Helium bags a great workhorse bag for a range of environments.
Helium Solo Down Sleeping Bag Regular (Comfort Limit: 13°C & Weighs: 415g)
Helium Down Quilt (Comfort Limit: Not Quoted & Weighs: 469g)
Helium 250 Down Regular Sleeping Bag (Comfort Limit: 2°C & Weighs: 706g)
Helium 400 Down Regular Sleeping Bag (Comfort Limit: -6°C & Weighs: 825g)
Helium 600 Down Regular Sleeping Bag (Comfort Limit: -11°C & Weighs: 1040g)
TransAlp Down Sleeping Bag
At 444g (Regular), the TransAlp Down Sleeping Bag blends lightweight design with reassuring warmth for milder conditions. It's 600-fill duck down and a narrow baffle layout that traps heat evenly without bulk, while the breathable, recycled shell fabric resists dampness. Mountain Equipment’s mountain fit is snug but not restrictive, with a shaped hood and footbox that work well for a natural sleeping posture.
The head-to-toe side zip is a useful touch, offering decent venting for warmer nights. Temperature-wise, it's best suited to around 8°C. The down lofts well after compression, and the construction quality is consistent throughout—this doesn’t feel like a compromise bag.
Women's Helium Series
Design wise Mountain Equipment's sleeping bags are superb, the hood and footboxes are particularly well-designed with multiple baffle sections to give them shape and structure. The Helium bags have a built-in neck collar rather than an out and out shoulder baffle — this saves weight and is pretty good in use.
The women's bags differ from the men's in that they are fitted for a shorter person and have smaller footboxes reflecting the physical differences generally speaking between men and women. The smaller women's footbox will feel warmer than the men's because it has the same amount of down in smaller chambers.
Women's Helium 250 Down Regular Sleeping Bag (Comfort Limit: 2°C & Weighs: 617g
Women's Helium 400 Down Regular Sleeping Bag (Comfort Limit: -6°C & Weighs: 762g)
Women's Helium 600 Down Regular Sleeping Bag (Comfort Limit: -11°C & Weighs: 948g)
Women's Helium 800 Down Regular Sleeping Bag (Comfort Limit: -15°C & Weighs: 1132g)
Helium GT Series
Efficiently Sized, Supremely Comfortable
Larger bags for side sleepers, big people or those people who don't like a close fitting bag. An extension to the Helium series the GT bags use the same principles of construction and high quality materials.
Reassuringly ME add more down to the GT series because its bigger, so the Helium GT 400 has more down in it than the standard Helium 400. This enables the two bags to achive the same EN test rating.
Furthermore there isn't a massive weight penalty for the extra comfort, just 70g in the case of the '400' bags.
Helium GT 250 Down Regular Sleeping Bag (Comfort Limit: 2°C & Weighs: 710g)
Helium GT 400 Down Regular Sleeping Bag (Comfort Limit: -6°C & Weighs: 894g)
Helium GT 600 Down Regular Sleeping Bag (Comfort Limit: -11°C & Weighs: 1114g)
Helium GT 800 Down Regular Sleeping Bag (Comfort Limit: -15°C & Weighs: 1300g)
Klimatic
The bag's standout feature is its sustainability. It uses 90% recycled POLARLOFT® insulation and 100% recycled fabrics for both shell and lining, making it an excellent choice for environmentally-minded outdoor enthusiasts.
The Alpine fit, anatomically shaped hood, and foot box maximise thermal efficiency, while the full-length zip baffle helps prevent heat loss. It's reasonably compact for a synthetic bag.
While not as compressible as down alternatives, the Klimatic offers reliable insulation even in damp conditions—a key advantage of synthetic fill. It's ideal for summer backpackers who prioritise sustainability and versatility in mild to cool conditions.
Women's Klimatic I Synthetic Regular Sleeping Bag (Comfort Limit: 6°C & Weighs: 735g)
Klimatic I Synthetic Regular Sleeping Bag (Comfort Limit: 6°C & Weighs: 749g)
Womens Klimatic II Synthetic Regular Sleeping Bag (Comfort Limit: -1°C & Weighs: 917g)
Klimatic II Synthetic Regular Sleeping Bag (Comfort Limit: -1°C & Weighs: 954g)
Women's Klimatic III Regular Synthetic Sleeping Bag (Comfort Limit -5°C & Weighs: 1200g)
Klimatic III Synthetic Regular Sleeping Bag (Comfort Limit: -5°C & Weighs: 1251g)
Xeros
Mountain Equipment’s Xeros Down Sleeping Bag is a finely engineered option for winter climbing and summit camps. At around 1010g (Regular), it delivers reliable warmth down to -12°C using 800-fill European goose down and a DRILITE Loft 10D shell that balances water resistance with good breathability.
The fit is close and contoured, designed to minimise dead air and maximise loft. Mountain Equipment’s EXL system, elasticated stitching built into the lining, draws the bag slightly inwards around the body, helping the down stay close to the sleeper and improving thermal efficiency without restricting movement.
Kryos
Mountain Equipment’s Kryos Down Sleeping Bag is built for cold, technical conditions where reliability and thermal efficiency are essential. At 1187g (Regular), it offers excellent warmth for its weight, with 743g of 800-fill European goose down housed in a DRILITE Loft 10D shell that combines light weather resistance with good breathability.
The fit is close and contoured, designed to minimise dead air and maximise loft. Mountain Equipment’s EXL system, elasticated stitching built into the lining, draws the bag slightly inwards around the body, helping the down stay close to the sleeper and improving thermal efficiency without restricting movement.
Sleeping bags are where Mountain Equipment started in 1961, and they still obsess over every detail to build the best bags in the world. Unmatched design expertise is combined with the finest materials and construction to give the best night's sleep in the mountains. This guide explains the range we currently stock of all ME Sleeping Bags.