Genuine LiftMaster K41-0566-000 12-tooth operator drive sprocket kit for #50 chain for the Maxum industrial DC operators.
Fitment: LiftMaster Maxum JDC7, RJDC7, JHDC7 and JHDC12 operators.
Standard fitment. A 10-tooth kit (71-1550B10LGH) slows the door about 20%.
Ordering the right part depends on the full model number, which is printed on the operator label. Call GateHouse Supplies if you are not sure — we service these units every day.