Casters - How can I tell which ones I've received?
Hard Floor Casters (also called Soft Casters): These casters have a rubberized coating on the wheels. If you look at the side of one of the wheels, the center of the wheel will have a matte finish while the perimeter around the edge of the wheels (about 1/4" from the edge inward) will have a glossy finish. This is the rubberized coating and therefore the Hard Floor Casters.
Soft Floor Casters (also called Hard Casters): If you look at the side of one of the wheels, the entire side will have a matte finish across the entirety of the side of the caster.