Many industries use coveralls to protect workers from harm. Some are designed for warmth, breathability, and/or protection (i.e. water resistance, hazmat, fire resistant, and so on), depending on what your industry needs.
Coveralls are used by different people ranging from skiers to factory workers to medical professionals and firefighters.
Coveralls are often designed to be reflective, insulated, windproof and waterproof. They’re the best type of protection from elements on the slopes.
Factory coveralls are mostly designed to be breathable, comfortable and durable. They protect the body and the clothes underneath from harm/damage in heated, cold or hazardous factory conditions.
Coveralls are also used for military purposes, such as in flight suits and have been used since the beginning of World War II. When aviation was developed, the cockpits were unheated - with low-oxygen, high altitude flying - so pilots needed warm clothing with multiple pockets with buttons, snaps or zippers to prevent them from losing articles when in flight and performing maneuvers.