Homelite Ryobi Part 678339003 used in models RY10518 18 in. 46cc Chainsaw, RY10520 20 in. 46cc Chainsaw, RY10519 Chainsaw, RY10521 Chainsaw, RY10519A 46CC Chain Saw, RY10521A 46CC Chain Saw, RY40502 Chain Saw, RY10519B RY10519B 46CC Chainsaw, RY10521B RY10521B 46CC Chainsaw, UT10548 14 In. 35cc Chainsaw, UT10568 16 In. 38cc Chainsaw, UT10588 18 In. 42cc Chainsaw, UT10549 14 In. 35cc Chainsaw, UT10569 16 In. 38cc Chainsaw, UT10589 18 In. 42cc Chainsaw, UT10640 14 Inch 42cc Chain Saw, UT10660 16 Inch 42cc Chain Saw, UT10680 18 Inch 42cc Chain Saw, RD905712 5700 Watt Generator, RD905712B Generator HOMELITE RYOBI 678339003 GENUINE Nut 5/16-18 Guide Bar REPLACES ALSO USED ON RIDGID TROY-BILT ECHO POWERSTROKE WORKFORCE BLACKMAX