Oregon 524076 0.325" Pitch 7-Tooth Consumer Spur Sprocket Oregon 524076 Replacement Consumer Spur Sprocket (Bearing 37325 installed) For .325" Pitch Chain Saws, 7-Tooth Sprocket Replacement schedule: Every two chain loops For Home lite 20, 23, 27, 2500, 2700, 3300, 3350, 3800, 3816, 3850, 4550, i3850b, i4150b, i4550b, PS-33, Timberman, UT10901, UT10910, UT10926 A simple, durable design for electric and small gas saws