Mont-bell Seamless Down Hugger Technology
Posted by Mark Richardson on Dec 12, 2022
To prevent down from shifting and producing cold spots, sleeping bags have been traditionally made with inner walls called baffles. The Seamless Down Hugger series is the world's first sleeping bag to remove the traditional baffles. This radical construction technique produces a sleeping bag with a single, continuous chamber and allows the down to loft to its fullest potential. This technique doesn't affect the lightweight and compact nature that Montbell's sleeping bags have become known for. The next generation of sleeping bag is here!
Innovative Design
A Eureka Moment - Eliminating the baffles
We asked ourselves, "Is there anything we can do to improve down's ability to insulate?" As ideas were being tossed around, one idea that came up was, by eliminating the baffles the down would be unhindered and each down ball could loft/puff out to its fullest ability. This extra volume of air trapping down would thereby increase the insulative properties of the bag. However, the catch is baffles prevent down from shifting out of place. When down shifts out of place, cold spots can form. This is when there is a spot in the sleeping bag that has no down coverage.
If Baffles Prevent Cold Spots, How Does Eliminating them Improve Warmth?
Our first reasoning was that if you give down more room to loft, we increase the layer of trapped air and we can improve the insulating performance of the down. Another reason, since sewing baffles into the sleeping bag creates holes in the outer fabric, the sewing holes are ways for warm air to escape. By eliminating most of the sewing lines on the bag, we are able to trap more air. However, in order to make our idea a reality, we have to remove the baffles and come up with a way that could hold the down in place. This was the biggest hurdle we faced when trying to reach that next step.
Spider Yarn: A Specialised Thread that Entangles Down
When looking for a suitable baffle replacement we received a little inspiration from nature, the spider. The thought was, "If we could make a web inside the sleeping bag, it could suspend the down and hold it in place, keeping the down from shifting." Based on this initial concept, work began on developing a specialized thread that could trap and hold down. Calling this new thread "Spider Yarn," we were successfully able to suspend a layer of down throughout the entire bag. This new construction is the "Spider Baffle System."
Spider Baffle System
Fabric
Excellent Stretch to Provide Better Sleep
The Spiral Stretch System (US.Patent No.7,900,301) is what made Montbell sleeping bags famous. The ability of the bag to move with you during the night has provided comfort for many. The Seamless Down Huggers are no different. Although the exterior of the bag is a solid piece of fabric, the interior of the bag features a combination of the fabric's mechanical stretch and elastic stitching. The result, the sleeping bag hugs and moves with you as you sleep, but doesn't feel restrictive. This also means that as you move, gaps between you and the sleeping bag are less likely to form and maintains even coverage of the sleeping bag, maintaining your warmth.
Ultralight Fabric
This ultra thin, lightweight fabric is strong for its weight. Because each individual thread is super thin and supple, the fabric is so light that it creates little resistance, allowing the down to fully loft.
Features
Mont-bell Seamless Down Hugger sleeping bags are cutting edge, eliminating relatively inefficient baffles from sleeping bag construction and incorporating stretch fabric to improve warmth without constricting the sleeper are two key technologies; on this page we explain those technologies.