vintage"Agent Fax" heat reveal GTE promo mug

This is a really cool 90's thing. Thermal reactive stuff was the hot thing back then. If there was a way to make it change colors or show something not already seen with temperature, it was done. This mug reveals a secret message when u pour your morning joe. The agent Fax promo was spearheaded when the facsimile was cutting edge. Ifykyk. I have 2 of these extremely rare mugs. I'm selling them individually.