If you are going to use a shim, adaptor, spacer or any other fudgin'-it device, and it's location is critical to safety, it should be high quality and strong. Interestingly, there are a bunch of crappy shims, adaptors and spacers out there that are dubious at best.
Luckily Nitto understands that testing and manufacturing a product so that it's safe, is important. Cold Forged, off-road safe, and heavier than other versions of the same thing 'cause they're strong!
Nitto makes a number of these. There's a number of quill lengths, and diameters of shafts quill diameters.
Our favorite usage of these is to put LD stems on Riv's, super hot!