The 510 Round Battery with LED Bottom [XTR713] is a compact rechargeable battery designed with an LED display and adjustable voltage settings. It features button activation, Type-C charging, and multiple press functions for convenient use. Features: Battery capacity: 320 mAh Size: 11.2 mm diameter x 108 mm height LED display on bottom Adjustable voltage by button Voltage settings: 2.1V / 2.5V / 2.9V / 3.3V / 3.7V Button activation Type-C charging port Preheat function: 2 clicks, 15 seconds at 1.8V Voltage adjustment: 3 clicks On/off function: 5 clicks