Fit Kit SET808 contains all the parts needed to thru-axle mount an Old Man Mountain bike rack to the rear of your bike with a 12mm rear thru-axle. This kit includes: - 12 x 223--229mm thru axle with 1.5 mm thread pitch - A pair of pucks - Clear protective tape - Stainless steel mounting hardware - Axle mounting increases our rack's load capacity to 70lbs/33kg - Fit Kits make it easy to swap between bikes or front and rear mounting with just a few bolts - Fit Kits protect your bike. Not all bike eyelets are meant for racks, most are only made for fenders or have very low weight limits. Axle mounting protects your frame We partner with The Robert Axle Project to supply our thru axles. Axle Length does NOT equal hub standard. This refers to the length of the axle shaft. All axles are compatible with +/- 2mm.