3" Black-White Twin Wheels Caster - M8 Threaded Stem3" Inch Black White Twin Wheels Swivel Caster with M8 Threaded Swivel Stem. 3" Inch Black White Twin Wheels Swivel Caster. This 3 model features a 75 lb load capacity and easy to attach threaded swivel stem. This twin wheel casters place more wheel surface on the carpet pile, and move in opposite directions to minimize carpet fiber twisting. 3" Inch Black White Caster Bearing Twin Wheel Caster Color: Gray Color Material: Nylon Diameter: 3" Inch = 75mm