The SRAM PC-1091 chain takes the fantastic performance of the 1090 to the next level. SRAM reshaped the outer links to lower running noise and increase overall durability. The 1091R's lower and complex shaped shoulders flow better and handle hard gear changes better than ever. The 1091R features of cut-out silver nickel plates connected with chrome-hardened hollow pins. It is also Shimano 10-speed compatible and is an OE replacement part for the SRAM Red group, but works with all SRAM groups. The PowerLock connecting link makes installation a snap.