Legacy 850 garage door openers with belt or chain drive opener option comparison model 2029 model 2029b model 2129 model 2129b ohd anywhere compatible accessory compatible accessory integrated battery backup not available standard accessory. Harness interconnect between the idcm and circuit board for the overhead door legacy 850 model 2129 and standard drive 650 1129 with ohdanywhere wifi connectivity garage door opener. This durable 1 2 hpc power plus motor operates most residential sectional garage doors weighing up to 500 lbs.