Helium GT Sleeping Bags

Efficiently sized, supremely comfortable

Helium GT

Designed for the long-haul and especially comfortable for those who like to sleep on thier side as well as their back, the Helium GT series provides greater comfort and more 'wiggle-room' without sacrificing performance thanks to thier significantly more generous yet tapered fit.


Built better

Made with PFC-Free and 100% recyc;ed fabrics and built with the same features as our standard Men's and Women's Helium sleeping bags, the Helium GT range of bags remain highly compressible and reliably warm for extended road trips through the seasons.


Features | Fill

Down is a unique and exceptional insulation. It is more compressible, longer-lasting, and offers better warmth for its weight than any other fibrous insulation, achieving this through a structure that traps maximum still air while weighing as little as possible. Geese, Ducks and Swans all possess down feathers underneath their flight feathers, but as all of Mountain Equipment’s down is a by-product of the meat industry, our down is only sourced from Geese and Ducks. The down is removed from the birds at slaughter and processed to make it clean, hygienic and fluffy.


700 Fill Power Duck Down

Our premium Duck down sourced from either within Europe or from China. With a cluster content of at least 90% and tested in individual batches to ensure a minimum fill power of 700. Some of the finest duck down available in the world and all DOWN CODEX® approved.



In 2009 Mountain Equipment became one of the first outdoor brands to introduce independent auditing of our down supply chain. Quietly introduced, without fanfare or press-releases, DOWN CODEX® set out to understand an industry and supply-chain that was largely ignored and certainly little understood.


All products contain a code that can be entered into our DOWN CODEX® website to trace the down that they contain. Not only can you identify the source of your down but the audit relating to that source and the down batch test results can also be viewed.



Features | Fit

The fit of a sleeping bag is crucial in optimising performance. A well-fitting sleeping bag is not only highly comfortable it also reduces dead air space and maximises thermal efficiency.

GT Fit

GT fit is roomy, comfortable and allows for a variety of sleeping positions.

Features | Fabric

Fabric technology is advancing all the time and we continually seek out those fabrics that offer the lowest weight, maximum breathability, compressibility and comfort.


All the Helium bags in the range use a Helium 20D outer fabric. Helium fabrics are our range of high performance woven downproof fabrics. Lightweight and ultra-compressible, Helium fabrics are the perfect choice for any product where weight and bulk are a prime concern. Their densely woven structure and use of fine denier yarns ensures these fabrics are down-proof, tear-resistant and highly breathable.


Downproof by construction, they do not use membranes and as such have unimpeded breathability. A nanoscale durable water repellence provides water resistance. Helium fabrics are constantly evolving as our fabric partners develop superior technologies. Weaving is a constantly changing field and in recent years the speed of developments has only increased. Before we commit to any new fabric, however, it undergoes extensive laboratory and field testing. Only the best survive.

Supersoft 20D

The inside of the Helium bags are all lined with 100% recycled Supersoft 20D lining fabric with PFC free DWR, chosen for its breathability and durability.

Features | Baffles

Baffle structure is crucial to the performance of down sleeping bags. Without it, even the best quality down will not loft and insulate to its full potential. Baffles affect a sleeping bag’s durability, weight, and the migration of down inside them – they are the building blocks from which sleeping bags are made.


Our neck baffles and entry-zip baffles are vital in reducing the ‘chimney effect’ of hot air flowing out of the sleeping bag’s openings, and are also useful in reducing the ‘bellows effect’ of the movement of a restless sleeper pumping warm air from the bag.

Slanted Box Wall Baffles

A slanted box wall baffle takes the classic box wall and offsets it to reduce thermal bridges and increase thermal efficiency. It also offers improved down migration control. An excellent lightweight construction technique that many other manufacturers would use in only their most premium bags.

Lode Lock™ Collar Closure*

Our Lode Lock™ collar closure with its low profile auto-locating closure combines all the advantages of a magnetic fastener with those of a mechanical lock. Rendering the traditional press-stud collar closure practically obsolete, its one handed quick release closure uses two captivated internal magnets to draw the locking mechanism together and ensure that once connected it cannot be accidentally opened. The result is an insulated collar that is more efficient and easier to operate. The collar’s down density is optimised so it moves with the user and contours to the body, while captive and elasticated drawcords ensure easy adjustment.


* Excluding the Helium Solo and Helium Quilt models.

Gemini™ Zip Baffle*

Our Gemini™ baffle is found throughout almost our entire line of sleeping bags. It is a unique zip baffle system which replaces the bulky, down hungry twin draft tubes used traditionally on cold weather bags. The Gemini™ system is light, efficient, low bulk and supremely protective. It is grown on to the sidewalls of the sleeping bag: the integrated zip baffle utilises a continuous V-baffle system paired with a shaped and stiffened underside. With a greater contact area than a traditional tubular set-up, heat loss by convection is significantly reduced and radiative heat loss minimised. Tested through every step of its development, it eliminates heat loss almost entirely and at a fraction of the weight and bulk of more traditional methods.


* Excluding the Helium Solo and Helium Quilt models.

Good Night's Sleep Guarantee

Every Mountain Equipment sleeping bag comes with a separate ‘A Good Night’s Sleep Guaranteed’ temperature rating.

Helium 250 GT



Helium 400 GT



Helium 600 GT



Helium 800 GT



Features | Hood and Foot Piece

The head loses a lot of heat and is very sensitive to changes in temperature, making good hood design crucial to the performance of any sleeping bag. A good hood will also keep the neck warm and reduce the ‘chimney effect’ of hot air escaping the body of the sleeping bag.


Cold feet can spell the end of a comfortable night’s sleep or even the end of an expedition and we have unrivalled experience in designing innovative sleeping bag foot pieces. By controlling the down in a sleeping bag, the foot is kept warmer, and ensuring the foot piece fits perfectly around the lower body is crucial.

DC5 Hood

A 5 baffle hood that provides high levels of down control, low weight and excellent insulation. Its roominess imparts excellent versatility and, combined with the easy-run dual tether draw cords, superb comfort.

Trapezium 4

A four baffle foot piece featuring our unique Bulls Eye™ Technology and offset Sharks Toe™ foot that is engineered for our lightest technical sleeping bags. Its baffle construction restricts down migration whilst keeping weight and bulk to a minimum.


Discover the Range

Helium GT

Light and packable enough for even minimalist trips in warm weather this bag still gives you a little extra room for added comfort.


Weight: 690g / 1lb 8.3oz

Good Night's Sleep Guaranteed: 1°C/34°F

A light, versatile and highly packable bag with a little more space for added comfort. The ideal choice for backpacking and travelling through summer and cooler spring nights.


Weight: 890g / 1lb 15.4oz

Good Night's Sleep Guaranteed: -5°C/23°F

Light, packable but with a slightly more generous fit this is the ideal bag for long trekking and backpacking trips through Spring and Autumn.


Weight: 1090g / 2lb 6.4oz

Good Night's Sleep Guaranteed: -10°C/14°F


A warm, comfortable and lightweight bag with a more generous fit for year round trekking and backpacking in cold conditions.


Weight: 1300g / 2lb 13.9oz

Good Night's Sleep Guaranteed: -16°C/3°F


Explore our Sleeping Bag Range

Get some sleep, tomorrow is a big day.

Perfectly adapted, the Mountain Equipment range of synthetic and down filled sleeping bags are the choice of today’s leading alpinists and arctic explorers. Ensuring comfort, protection and reliable warmth in the most extreme of environments. 100% of our down is Down Codex® approved and comes from independently audited and traceable sources.


Discover the range

Extreme Alpine


Extreme Light