![Picture of KRC Pro Series R-LOK Serpentine Water Pump Pulley Only Picture of KRC Pro Series R-LOK Serpentine Water Pump Pulley Only](https://cdn.performancebodies.com/pbfilestore/PartsCatalog/imgPar552598_552598.jpg)
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• 4" main 6-groove with 3.5" 3-groove front accessory drive black anodized to 62 rockwell hardness
• R-LOK crank system allows for an endless amount of crank pulleys to be stacked and locked together providing a more positive and lightweight drive than a conventional mandrel system
• R-LOK system is more concentric and truer than the conventional pin-drive systems