Chamberlain Liftmaster universal coaxial commercial receiver. Security + rolling code technology and/or billion code, DIP switch compatibility, and an external 8" whip antenna included. Jumper options of 12V DC or 18-35V AC/DC, high security memory stores up to 15 security + remote controls or keyless entry codes. Normal security memory store up to 31 Liftmaster remote control codes of any type. For use with 371LM OR 373LM & 377LM KEYLESS ENTRIES