Remote Features : Code-Hopping Encryption Unique antenna design incorporating the Keyring increases operating range by 50% Crystal frequency-controlled within +/- 100KHz Frequencies available are 403.55MHz and 433.92MHz 12V Battery operation – GP23A Alkaline Cell Typically 2 years battery life expected under normal use LED flashes when there is a low battery condition Rubber buttons are easy to press and click positively