Linear act-22 keychain garage door opener Features and Specifications Linear Moore-o-Matic Megacode system 2-button mini ""key chain"" size transmitter for gate or garage door openers (2"" by 1"") Smart coding system, no dip switches, 318 Mhz frequency 3V lithium ""button cell"" batteries and a key ring included Long-life battery, should last up to five years with normal use Compatible with ALL Linear Megacode System products