RockShox 142- mm 1.75 174 mm Flat Thru Axles
About RockShox - "An icon in the mountain bike industry."
The inside-to-inside measurement of your fork or frame at the dropouts.
The length of the axle from the base of the head to the end of the threads, in millimeters.
Usually flat or conical. This is the shape of the washer and should match your frame or fork.