Insulated coveralls are a one-piece garment designed to fit over normal clothing to protect the wearer from freezing temperatures. The insulation is usually provided by a lining of cotton, nylon and polyester fiberfill.
Coveralls can be worn year round. They protect the wearer's clothing from becoming soiled or wet during manual labor. Insulated coveralls add another function by keeping the wearer warm while performing manual labor. The insulation is provided by a layer of material sewn on the inside of the coveralls. This material may be flannel, down or polyester. Quilting of the lining provides additional warmth because it helps trap body heat. Coveralls are often confused with overalls. The difference between the two is that overalls only cover the legs and chest, whereas coveralls cover the entire body other than the head.