Fourth Element's Xerotherm range is a great baselayer for wearing with your drysuit.
The vest is the perfect option if you are just looking for additional layer of warmth on your core. The sleeveless design means there is no restriction of movement to the arms. There is minimal bulk with the vest making it very comfortable to wear as well as riding the affects this has on your buoyancy.
The Polartec® Powerstretch® material, originally developed for NASA, works by trapping a layer of air between your skin and the material, providing excellent thermal protection. The Xerotherm range can be worn alone under your neoprene drysuit, or with another undersuit for extra warmth.
The fabric is the fast wicking, removing moisture from the skin and spreading this out on the external layer of the material, maintaining the layer of air between the material and your body.
Xerotherm is popular with FBI Dive Teams, the Norwegian Navy and British Police Dive Units.
