StayWarm StayCool is an authorized reseller of TechNiche products. TechNiche is the leading brand in cooling and heating apparel and Accessories! We offer the best in cooling vests and accessories. We have two different cooling technologies, evaporative cooling (HyperKewl) and Phase Change Cooling (CoolPax). Our HyperKewl cooling technology is a one of a kind super absorbent fiber material that absorbs water and cools you off as it evaporates. The unique thing about HyperKewl technology is that it doesn't bulk up or becoming slimey when you activate it with water.