Kadee knuckle couplers are among the most robust and reliable magnetically activated automatic couplings available. The knuckle design replicates the design and function of the Buckeye knuckle couplers fitted to British passenger coaches since the 1950s and now used increasinly on heavy block freight trains.
Setup of the Kadee couplers will vary from model to model and layout to layout. Frequently aligning the rear inside face of the knuckle with the end of the buffers will provide adequate clearance. Many British OO models will operate satisfactorily with the no.19 long shank coupler, however some models have a more deeply recessed coupler mounting requiring the extra long no.20 coupler.