Enhanced Radio TechnologyTM rolling code and/or DIP switch compatibility. 315MHz; External 8 in. whip antenna included. Momentary or constant contact, jumper selec. Two-piece aluminum case; detachable cover. High security memory stores up to 18 Enhanced Radio TechnologyTM remote controls or keyless entry codes. 12 volt DC or 18 – 35 volts AC/DC jumper selec. Normal security memory stores up to 31 LiftMaster® remote control codes of any type