Heddolf remotes and Heddolf garage door opener remotes are based on frequency mainly. They are are 9 dip switch trinary remotes except for the 300mhz multicode clone. The rest of the heddolf remotes are based on 312mhz, 318mhz, 340mhz, 360mhz, and 390mhz and covers a variety of other brand name garage door openers. Heddolf garage door openers by the Keystone corporation are compatible with "Overhead Door", "Crusader", "ESP MICOM", and "Intercontinental Dynamics" garage door opener parts and remotes. There are only a few made any more and most can be replaced by the Skylink 69N keychain remote or Carper mini keychain remotes. The rare versions are the heddolf 360 mhz and heddolf 340 mhz which still exist today as visor size and one keychain sized garage door opener remote. Call us if you need help finding the right garage door opener for your needs. Heddolf Keystone is among the world's largest manufacturers of radio control products. With more than 20 years of experience offering typical German quality and reliability in design development, plus an efficient, low-cost production facility in China, you can depend on Heddolf Keystone to provide a quality product at an affordable price.