Hot water suits were introduced in the early 1970’s. Principally employed in the Offshore industry, and used by divers for extended diving periods, including saturation diving.
These suits are fed by heated water from the surface which circulates inside the suit, and reaches the divers body through holes drilled in rubber tubing which is fitted throughout the suit.
Temperature is regulated by the diver communicating with the surface team, and the water flow can be controlled by the diver by way of a valve fitted on the thigh of the suit.
Hot water suits are also used by commercial divers, and military divers.