Sunstopper 2.0 1/4 Zip Baselayer Our popular Sunstopper base layer is back and better than ever with updated styling and exciting new colors. Same great performance features but now with a raglan-cut sleeve for a flattering fit and breathable tech mesh paneling in all the places you need it most. AriatTEK Heat Series technology keeps you cool when the competition heats up Moisture Movement Technologyâ„ keeps you drier Sun Protection Fabricâ„ with UPF rating of 45 provides protection from ultraviolet rays Fabric inhibits the growth of bacterical odors Cooling technology reduces skin temperature Lightweight pique knit Stand collar with 1/4 zip styling Breathable mesh paneling