Bolts are made from billet alum, anodized for corrosion protection and have two alum. crush washers that are included with each fitting to seal the bolt to the fitting. Fitting has a .750" hex head with a .560" shoulder that will register in the fitting. Under the head to the last thread is .925" and hole down the center is .250".
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.