Motor assembly replacement for belt drive and chain drive model garage door openers listed below that came with a battery back-up or are battery back-up capable. 

• Motor Assembly includes: Motor, Optical Encoder with encoder cover (RPM Sensor), the wiring harness attached, and the instruction sheet 
• Genuine Genie replacement part 
• Compatible with models: 1055B
• Replaced old part number 40966R.S