If you have a Genie garage door opener that features split-rail screw drives, this component replaces the coupler for the screw rail closest to the motor. If the motor is running but the screw in the rail section closest to the motor is not turning, this coupler needs to be replaced. If instead, the closest section screw is turning, but the screw in one or both of the other sections is not turning, then the collar and spring clip, 19806A04 and 19807A04, need to be replaced. The collar and spring clip connect the screw in the 2nd and 3rd rail sections to the screw in the first section.