The quartz dual heating element delivers pure flavor, while the functional heating element cap prevents concentrates from leaking and keeps the mouthpiece from overheating. The Evolve Plus fits perfectly into a 14 mm female downstem to operate as a portable eNail. Built-In Concentrate Jar Dual Quartz Wax Heating Element Larger Chamber Micro-USB Charging Upgraded Battery Sleek and Discreet Available colors may vary