The STUN MASTER 800,000 Volt CELL PHONE STUN GUN is very simple to use. Turn safety off, touch assailant with end of stun gun and press the trigger (round button on keypad). Because it looks like a harmless cell phone, it will be easy to surprise an attacker. Remember, the purpose of this stun gun, and all other non-lethal self defense products, is to give you time to escape. Use the cell phone stun gun, then run for safety. Don't stand around waiting to see if your attacker is going to get back up. Uses 2 CR-123A Lithium batteries (not included). Free nylon holster with belt loop included. 4.75 inches tall x 2.13 inches wide x 1.25 inch thick. Comes With Free Leatherette Holster