This is a A-RC120M Metric Roller Chain PN: RC120MMain Description As Following : A-RC120M Metric Roller Chain P.N: RC120M B1: 1" / 25.4 MMD1: 25.4 MMD2: 14.63 MMDIN: 24 B - 1Length: 16'P: 1 1/2" / 38.1 MM Crossed From: 24B MISCELLANEOUS Found in Section & Models : Chains/ Sprockets/ Pulleys/ Hubs > Metric Roller Chains and Attachment Links, (Miscellaneous) (UNDEFINED): SEVERAL Associated Items : A-CCL1112, A-CL120M, A-OL120M Also This is An Aftermarket Product And : D1: 25.4 MM DIN: 24 B - 1 Length: 16' Pin Diameter: 14.63 MM Pitch: 1 1/2" / 38.1 MM Width: 1" / 25.4 MM