The voltage changes by turning the wheel from 3.3V to 4.8V. Five consecutive clicks will turn on or off the battery. Two consecutive clicks activate the Preheat Mode; the battery will be on for fifteen seconds with 2.OV before automatically shutting off. 
The Cookies Slim Twist vape pen battery charges with included eGo-USB charger, it connects to the AC/USB adapter with a maximum output of 5.OV/O.5A. The battery has low voltage, short-circuit, and overcharge protection.
FEATURES: 
Brand: Cookies
Connect: 51O Thread
Capacity: 900mAh
Voltage Range: 3.3V - 4.8V
5-Clicks: On/Off Switch
2-Clicks: Preheat Mode 0n / 1-Click 0ff
Atomizer Protection
Short Circuit Protection
Low Voltage Protection
Overcharge Protection
Charging: eGo/USB Charger 5.OV/O.5A
Length: 108mm
Diameter: 14mm
Weight: 30g
INCLUDES:
1x Cookies Slim Twist Battery
1x eGo-USB Charger