Emaxx™ Caster, Swivel with Brake, 4" (101.6 mm), Envirothane™, 1000 lbs. (453.6 kg.)iLock braking mechanism provides performance and durability unparalleled in the marketplace 3 4" diameter heavy duty kingpin 1 2" zerk axle and lock nut 5 16" diameter upper race; hardened steel load bearings Roller bearings with drilled hardened steel spanner bushing and plastic side washers Virtually maintenance free Corrosion resistant bright zinc finish Excellent for stock carts, platform trucks, heavy service equipment, garbage bins, wire