For Genie garage door openers. Mounts on rear of opener rail and fits in motor head. Typical symptoms of a stripped Screw Coupler is a grinding noise coming from the rear of the motor head. The motor turns but the screw does not. On Genies with no clutch nut coming out of the back of the motor head, there is a small plastic coupler that connects the screw assembly to the main power head. To check and replace that part, remove the two screws holding the rail to the main power head. Note: If the screw assembly on your Genie garage door opener protrudes out the back end of the main power head, you do not have a "clutchless" opener, and there is no coupler on that opener. Genie original part.