Warp 9 Stem lockDifference between Fender mount and no fender mount Fender mount: Means its compatible with the warp 9 fender mount No fender mount: Means you can run your stock fender mounting to your fork just like you would without a stem lock. this is the choice for most people This is a must do upgrade if you are upgrading to a direct mount stem. Are you fighting your head bearings coming loose? Chances are good the oem star nut keeps walking up the steering