Add an extra layer of warmth! The ultimate tool for being warmer during your open water swims, the Adjustable Thermal Skull Cap features high quality 3mm Yamamoto SCS coated neoprene paired with our unique Zirconium thermal liner found in our Thermal Reaction wetsuits. The SCS coating reduces drag making the swimmer more streamlined. By incorporating our Zirconium internal jersey we reduce water absorption which helps create an extra boundary layer to protect against heat loss, in addition the cap is softer and more comfortable. After many complaints of a tight chin strap, we updated the Thermal Cap to include an adjustable chin strap with velcro closure. Simply adjust the strap to where it feels comfortable but secure and trim off any excess strap with sharp scissors.