As a veteran of the outdoor industry, sierra Design has made many new mountaineering equipment over the decades, including the first tent to use pole connection technology and straight poles, and the first sleeping bag on the U.S. market with 700 expansion down and head shrink wrap design.
 
sierra Design also boldly cancels the zipper of the sleeping bag opening, and uses a large arc sleeping bag piece instead, giving the user a sense of use like a quilt, but the airtightness of this design lacks guarantee, which relatively restricts the use of the environment, and is more suitable for use in the case of less wind and stable temperature, and is not recommended to choose when it is windy in mountaineering or winter.
 
At present, the latest CLOUD 800 sleeping bag has used 800 expansion down, with a zipperless design, and is priced at around $300. If you value airtightness, you can choose the NITRO 800 with the same expansion of 800, which retains the traditional mummified design, and even the sealing mouth is smaller, only the mouth and nose can be exposed, so the waterproof treatment at the collar is targeted to avoid the moisture generated by breathing from wetting the sleeping bag, and the side wall is also equipped with side walls to prevent internal and external temperature convection, and the heat retention is better. There are special anti-hook zipper rails for more convenient use, and the price is under $400.