Ordinary cotton sleeping bags are made of polyester or nylon, and polyester nylon fabrics vary in density and texture. 

Down sleeping bags have a high requirement for internal and external materials. The lining material is usually more than 

200T. Because the lining material index is lower than 200T, individual hairs will wear out. Some of the better sleeping bags 

often use good nylon material to ensure that there is no phenomenon of fleece wear out. This material is light and feels 

soft when the skin is in contact with it. The material inside and outside the down sleeping bag needs to have good air 

permeability, otherwise the moisture released will accumulate in the sleeping bag, so that the down warmth is greatly 

reduced. High woven cotton or polyester can also be fleece-resistant, but the weight, poor compressibility, generally not 

used in high-end sleeping bags.

  Sleeping bag external material: good down material is waterproof and breathable, because in some very cold places, 

every morning, when the heat inside the tent condensation of small drops of water, often splash on the sleeping bag, 

so the external material of the sleeping bag must have a certain waterproof, to ensure that the sleeping bag dry. 

Down sleeping bags are made of waterproof and breathable materials, as they lose warmth when wet and dry.