The ego T 900 mah battery is perfect for ce4 clearomizers and other basic cartridges. Compatible with all 510 tanks. The battery has a 5-click on/off feature. Press the button five times within 2 seconds to lock or unlock the battery. The battery LED will blink blue when switching modes. When the battery is in lock mode, the button is disabled and the battery will not power the clearomizer, atomizer, or tank.