Hub is made from heat treated steel that has been black oxide coated for corrosion protection. The hub uses two .250" keyways to register into the bearing support hub and has the provision to run a .500" bolt thru the center to tie into the crank bolt.
Note: This is a used item. This item might have been taken in on a trade. RBS may have inspected this item and deemed re-usable. There is no warranty expressed or implied with this item.