9 - speed Chain .NEW for 2006 - PC 951; PC 971; PC 991 and PC 991 Hollow Pin .- - - - - - - - - - - - - PC - 991 Hollow Pin: buldged outer plate design chamfered inner link design improved PowerRollers HollowPin riveting process 114 links - - - - - - - - - - - - - - PC - 971 Like the PC - 991, the PC - 971 features inner and outer plate designs that offer faster and more accurate shifting at a more affordable price point .The PC - 971 uses nickel - plated outer and grey inner plates .- - - - - - - - - - - - - - PC - 951 The PC - 951 is our most economical PowerChain while still maintaining our high standards of quality .Like all Power Chain II chains, the PC - 951 uses Chrome Hardened rivet pins for increased durability .