This is SSD's steel 1.9" 3 piece wheel. It comes with all the bolts needed to assemble and a few extra scle bolts in case you lose any.
Supershafty recommends putting locktite on all the scale bolts as they come pretty loose from the factory.
We have tested them on RC4WD wheels and they mount up pretty easily for a 3 piece design. We have not gotten to test other brands yet. We cannot guaruntee fitment on all types of wheels, but SSD has made a great product here.
These come in packs of 2.