Chris and Katy from Robert Axle Project are avid mountain bikers, trail builders, bike tourers and BOB Trailer enthusiasts who wanted a way to connect various bike trailers with their thru-axle equipped bikes The Robert Axle Project supplies a 12mm thru axle adapter for bike trailers 12mm thru-axles come in several lengths and thread pitches. It is important to purchase a Robert Axle that has the same thread pitch as your bike Adapters work with many Hitch Mounted Trailers - Thule, Burley, Chariot, Croozer, etc. Solid axle is precision CNC machined from 7075 aluminum, one of the strongest aluminum alloys available Hard black anodized for rugged durability Includes stainless steel axle end which allows for mounting of the accessory of your choosing No special tools required. Robert Axle is installed or removed using your multi-tool hex key Designed, built and tested in the USA NOTE: Thru-axle lengths do not equal hub standards. An axle has to be longer than the hub to fit in the frame. For example, a 12x142 hub standard does not equal a 142mm long axle