Giant CXR1 EndcapsThese endcaps for the Giant CRX1 convert the 12 X 142mm rear hub to a 5 X 135mm QR hub. A quick release axle makes the wheel much easier to install and remove from the frame. Make sure the frame you are installing the wheel on accepts 5 x 135mm axles. FeaturesConverts 12 x 142mm hub to 5 x 135mm QR hubCompatible with Giant CRX1 Bike