The standard 991 chain sets the standard for a high end, reliable chain that works well, installs easy and doesn't cost a fortune. It serves as a standard replacement to any Shimano or SRAM 9 speed drivetrain - road or mountain. Both inner and outer plates are nickel plated for durability and longevity. Aesthetically, the nickel plates look great and clean up nice. PowerLink connector is child proof and a snap to install.