The ultimate baselayer for use under a drysuit.Constructed from Polartec® Power Stretch® fabric originally developed for NASA, the Xerotherm traps a layer of air next to the skin—providing far superior insulation compared to water. This design keeps the diver warmer, drier, and more comfortable throughout the dive. The Xerotherm range is engineered to be worn under another undersuit for added thermal protection or on its own beneath a neoprene drysuit, offering flexibility across a wide range of diving conditions.

The unique knit structure of the Xerotherm fabric delivers the fastest moisture-wicking performance of any product in the Fourth Element range. Moisture is drawn away from the skin along fine fibers and dispersed across the outer surface of the fabric, maintaining a thin, insulating layer of air next to the body. This moisture management is so effective that some divers report experiencing minor drysuit leaks during a dive without noticing until after surfacing

The performance is superb,” said world-renowned, award-winning underwater filmmaker and author Doug Allan after testing the Xerotherm in 29°F (-2°C) water inside the Arctic Circle in Svalbard while filming for the BBC production The Blue Planet.

The Xerotherm is trusted and specified by FBI Dive Teams, the Norwegian Navy, and British Police Diving Units, making it a proven choice for professional and recreational divers who demand reliable thermal performance under a drysuit.