Part is off a year 1986 Yamaha Moto 4 YFM200DX ,  fitment for the early year YFM 200 moto 4 1986 thru 1987..   Good working rear differential set on atv and in hand working. The original  bearings spin and feel decent, all the splines are good with no wear as shown, all the threads are good. The matching prop shaft is good.