7.7" overall. Rechargeable. Tailcap switch. Water resistant. Impact resistant. Powerful white LED that never needs replacing. High, medium and low white light output modes. Very large power bank (5200 mAh) will charge 2-3 mobile phones. Built-in USB charging port and USB-power out for charging a mobile phone or other devices.Color coded battery charging indicator. Non-slip ribbed aluminum body with ultra-tough polycarbonate lens. Requires (1) Lithium battery (included). Clam packed.