QualityParts From Oregon That you can depend on. For drive belt and mower deck on many 12-22 HP front engine tractors: Outer-diameter: 3-7/8", flat-outer-diameter: 3-1/16", flat-width: 3/4"; Overall width: 1-3/32", bore: 3/8"; Replaces AYP 173438, 104360X, 131494; ; ; Oregon Equipment Parts 34-046 Idler Pulley Flat Ayp[756]