Dry suits are also worn by rescue personnel who must enter, or may accidentally enter, cold water. Features of dry suits designed for rescue may be a hybrid of the immersion survival and work suits, since the wearer is not expected to be working in the suit for an extended time. They may also be optimized for a specific task such as ice rescue, or helicopter rescue swimmer.
A drysuit provides thermal insulation or passive thermal protection to the wearer while immersed in water and is worn by divers, boaters, and others who work or play in or near cold water. A dry suit normally protects the whole body except the head, hands, and the feet. -?Wiki