The scaffold heavy duty caster wheel is made of a cast-iron wheel with a rubber overlay that is 2 inches wide with more than one inch of rubber covering the iron caster wheel. There are ball bearings in the pivot mechanism to handle high loading. Double zinc grease fittings. Double lock to maintain rigidity. Locks to prevent wheel pivot and locks to prevent the scaffold caster wheel from rolling. Upper steel body is galvanized. Hole location on stem is 3.25 inches from the base.is galvanized. Hole location on stem is 3.25 inches from the base.