Pro Spur Sprocket / .325" Pitch, 7 TeethPack Size:1Echo 17510514630, Echo A556000020, Echo A556000021, Echo 17511412530, GB EC206-J7N, Ref No SEC206-27NNHC 085-2257, NHC 085-5977, Oregon 51344, Rotary 12038, Stens 085-225Echo CS400, CS440, CS3900, 3600, 4510, CS4200, CS4400, CS4100, CS3700, CS4500, CS510, CS520 and CS530; John Deere 45, 46 AND 450Pitch: .325", Crank Diameter: 10 mm, ID: 2.750 ", Teeth: 7, Bearing included