The SKYLINK MK-318-3 3 Button Garage Door Remote Key Fob provides a compact, pocket-sized access for up to three skylink-brand garage doors. The remote control has three buttons and a key fob for convenient transport in your bag, pocket, individual or housekeys. Rolling technology is used in communication with the receiver, changing access after each use to prevent unwanted access. A 3V lithium battery model is included (CR2032). skylink-brand or other compatible receivers are required (not included). Overall Dimensions: 2.25L x 1.12W x 0.25H in. Works with up to three electric SKYLINK 3V lithium battery life included. Wide operating range operates from 100 feet. Manufacturer Warranty 1 year.