Battery type: 18500 Lithium-ion
Battery voltage: 3.7V
Needle protrusion：1.5-5mm
Power intake: 5W
Rated capacity: 1900mAh
Charging input: 5V/1A
Charging t ime: 3-4 hours
Usege time: 4-6 hours
Adjust voltage by angle

Most important thing before using EP9 pen is that put the battery into the pen correctly!