The iKrusher Slim Pen battery is designed to utilize 510 cartridges. The iKrusher Slim Pen battery features a single button operation, 280mAh capacity, variable voltage, and Pass-Through charging. The voltage can be switched with three quick clicks on the button and the LED light will change the color according to the voltage red - 2.8V, green - 3.3V and blue - 3.8V. Five clicks will turn on or off the battery. The iKrusher Slim Pen battery can be charged through Micro-USB port on the bottom at 5V/0.5A. The battery has low-voltage, short-circuit and overcharge protection.