The pc x1 chain comes from a long line of dependable lightweight chains that are built for toughness designed with srams trusted xx1 geometry the pc x1 features solid pin construction 11 speed powerlock and smooth efficient shifting that you can count on every time out powerlock174 sram chain engineers developed powerlock as a tool free sure and consistent way to connect our 11 speed chains while pl does not require special tools for install the especially tight tolerances of 11 sp