Yocan - UNI Pro 650mAh Variable Voltage Carto Battery Mod 

Compact Design
Powered by: Built-in 650mah battery
Charged through: Micro USB
Magnetic 510 connector ring is included
Five Click On/Off feature
Three Click 10 Second pre-heat feature
Preheat functionality
Activated by clicking the power button 2 times.
Preheat function runs for 10 seconds
OLED Display: