They just slip on over the kingpin, tight fit over the widest part but they'll go on. It helps if they are warmed up just a little. I wouldn't use anything else.
2004.5 GMC SLT CCLB, Ride Rites, Turbo brake, EFI Live
2012 Arctic Fox 29 5T 5th Airborne, B&W, Prodigy
Papillon navigators Lily, Buddy and Willow