THE HEATER CORE. Inside each EVO is the patented PerpetuHeat Thermal Technology. This advanced technology automatically adjusts the heating to a person's inhalation rate, ensuring smooth, rich, and consistent vapor. As you inhale, the air flows past the heater, warms up to your set temperature and then glides through to vaporize your chosen herb or concentrate. The EVO utilizes convection heating technology which provides superior heating and vaporization when compared to conduction heating. Most other devices utilize conduction heating which consists of a hot surface that actually chars the herb, leading to that all too common burnt taste.