Robert Axles for Kid Trailers are designed specifically to fit your 12mm thru-axle bike and allow attachment of any hitch-mounted trailer. These fit any trailer that has two wheels and a single point of attachment to the axle. This includes all the two-wheeled child, pet and cargo trailers such as: Thule, Chariot, Burley, Instep, Carry Freedom, and many more. Purchase our Kid Trailer axle for your bike. Share your stoke for cycling with your kids. Simplify your life by allowing quick and secure attachment of your trailer to your best and favorite bike. Enjoy the adventure. This axle is specific for bikes with the FOCUS R.A.T. thru axle system and 12×142 hub spacing and comes with a replacement R.A.T. nut found on the derailleur side of your bike. Our nut is threaded (M12x1.5) to accept our solid high-strength Kid Trailer axle.