The Optical Encoder also sometimes called an RPM sensor, is compatible with the Genie model chain and belt drive garage door openers that are listed below. The optical encoder may help resolve problems of short traveling or issues with drifting limits on the garage door opener. Compatible with these Genie models that have RIDE motors: 3120H, 3120H-B, 3120H-L, 3120HL-B, 7035, 7055, 7055D Genuine Genie Replacement Part To identify if your garage door opener has the RIDE motor compatible with this optical encoder use this tip. The previous motor will have a label with the brand name “NIDEC”. The RIDE motor will only have black barcode stamping as shown below.