It's rechargeable so you never have to buy batteries. It's 21.5 inches long when fully extended, and only 13 inches when collapsed. The full length of the metal part is electrified. If the attacker tries to grab the Telescopic Stun Baton from you, he will be shocked. A push of the trigger immediately expands the Telescopic Stun Baton and starts shocking. Just push it on the end to collapse. Very easy to do. Don't worry about being shocked should the attacker be touching you. Won't happen! The current will not pass to you. Will shock through a 1/2 inch of clothing. LIFETIME WARRANTY. 21-1/2 inches long when extended. Only 13 inches long when closed. Comes with a FREE holster (a $15.00 value) for easy carrying. Comes with easy to use recharger. The Telescopic Stun Baton will come to you about 30% charged so it can be used right out of the box. Just plug it in for about 10 hours to fully charge