The 81RGD Raynor remote was often used with the 520RGD & 540RGD models of radio receivers on the older Raynor garage door openers. They often can be found on the models R130, R150, R170 and Flitestar openers to name a few. The radio receivers could hold a total of four programmed 81RGD 1-button remotes. The 81RGD compatible radio receivers can be identified by the Green Learn button found inside the radio receiver or by looking on the back of the radio receiver where you'll find the model number of radio receiver printed. The 81RGD Remote was discontinued but the Liftmaster 893MAX Remote can be used as a compatible replacement.