They make 2 different covers. Which one you have? I dont remember.
Replacement Sprocket cover for Stihl models 038, 044, 046, 064, 066, MS440, MS460, MS660. Includes bumper strips and rubber guard.
Replaces OEM # 1122 648 0401.
http://northwoodsaw.com/store/index.php?l=product_detail&p=237Replacement Sprocket cover for Stihl models 024, 026, 028, 029, 034, 036, 038, 044, 046, MS240, MS260, MS270, MS290, MS310, MS340, MS360, MS380, MS440, MS460.
Replaces OEM 1125 640 1701, 1125 656 1501, 1121 648 6610 .
http://northwoodsaw.com/store/index.php?l=product_detail&p=1195