Add an extra layer of warmth! The ultimate tool for keeping warmer during your open water swims, the Thermal Skull cap features high quality Yamamoto neoprene paired with our unique thermal liner found in our Thermal Reaction wetsuits. 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. For 2021 we've updated this popular product to make the chin strap adjustable with a velcro closure. Simply adjust the strap to where it feels comfortable but secure and trim off any excess strap with sharp scissors.