What are the 4 different types of cooling vests?

Evaporative - Must be worn wet, and can be slimy, and heavy.

Ice - Can cause skin burns and hypothermia, condensation causes the garment to be wet and because it’s so cold it has to be worn on top of clothing. 

Cool Flow or Active - Must be connected to ice water and external pump. Works by pumping cold water through tubes in the garment.

PCM (Phase Change Material) - ThermApparel’s Cooling Vest type. Won’t cause ice burn, won’t get you wet, has no tubes, and fast recharge time.