Reaction Sleeveless Wetsuit (MEN'S)The Sleeveless Reaction is purpose built for the most efficient swim while keeping you cooler in warmer water. Matching the redesigned Reaction wetsuit, the Sleeveless Reaction takes all the key performance upgrades and removes the full sleeves. This allows better heat regulation to keep your core temperature lower when the water is warmer while still encouraging natural body rotation, increasing distance per stroke and increasing comfort in the neck.