Black Plastic Caster Wheel 30mm Inch Swivel Plate Caster with 75lb. Load RatingBlack Plastic Caster Wheel 30mm Inch Swivel Plate Caster with 75lb. Load Rating Black Plastic Caster Wheel 1. 18" Inch with Metal Plate for Chair. This black plastic twin wheel casters place more wheel surface on the floor and carpet pile, and move in opposite directions to minimize carpet fiber twisting. Perfect used on furniture, office chairs, printer stands and entertainment centers. Item: 30mm Inch Black Caster Bearing Type: Swivel Plate Caster