Maxpower 7978 Flat Idler Pulley Replaces Murray 421409, 91179 and Stiga 1134-4686-01 Engine to transmission idler. Fits 38 Inch Cut 12 hp lawn tractor 1987-1993 3-11/32 Inch OD, 1/2 Inch ID, 11/16 Inch Height Composite: glass filled nylon