041D8615 Liftmaster Shaft Collar for Side Mounted Garage Door Units like the 8500, 8500W, 8900W, 3800 and 3900 models.
This collar - coupler design has been improved and strengthened. Open Door Discount Remotes has this item in stock
041D8615 Liftmaster Door Shaft Collar Coupler, RJO 041B6299, 41B6299, 41A6388