Heddolf garage door opener remote control transmitter model P220-1K (same as Allstar, Allister or Pulsar model 921-318). Also is compatible with Mighty Mule / GTO PRO. Replaces Pulsar, Allister /Allstar / Mighty Mule / GTO PRO brand gate or garage door openers. 1- Button single channel remote control transmitter. 318 MHZ Frequency visor size gate or garage door opener. Nine (9) 3-positions (binary) dip switch format, clip and battery included. Also available in key-chain size, the Carper model 318 is a direct compatible replacement.