This is a brand mower idler pulley. The specs are as follows: For double "V" drive wheel pulley to gear and positive drive belt. Fits 36", 48", 54" and 61" mid-size. B 4" C / Bore 3/8" D 1-9/16" E 3/4" F 13/16" H 7/16" T .060" Replaces part numbers...