Robert Axle Project 12x142 1.0mm Thread for Hitch Mount Trailer Axle shaft is machined from 7075 aluminum and hard anodized For use with hitch mount style trailers common with child carriers such as Thule/Chariot, Burley, InStep, Croozer and more Materials: 7075 Aluminum and 303 Stainless Steel Application: Hitch Mount Trailer Installed or removed using a 5mm Allen wrench