Now thermal imaging is on the Zentek web site, showing what everyone has been experiencing wearing the vests. The first image shows a man pressing his hand against the vest and the resulting heat absorption. This happens in only 10- 20 seconds. The second set show the model slowly waving the vest in the air , as air flow discharges the heat. The model wore the vest for 1/2 hour first. Normally a breeze or movement of the wearer discharges the heat. To hold the heat in, the wearer either puts on a sweater ( insulation) or adds a lightweight layer on top of the vest.