This is a A-OL40M Metric Offset Link w/ Cotter Pin PN: OL40MMain Description As Following : A-OL40M Metric Offset Link w/ Cotter Pin P.N: OL40M Used W/ RCKE12516 Metric Roller ChainPitch: 1/2" / 12.7 MMWidth: 5/16" 7.75 MM Found in Section & Models : Chains/ Sprockets/ Pulleys/ Hubs > Metric Roller Chains and Attachment Links, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : New Also This is An Aftermarket Product And : Used W/ RCKE12516 Metric Roller Chain Pitch: 1/2" / 12.7 MM Width: 5/16" 7.75 MM