Mastercaster Duet twin wheel master casters Duet Twin Wheel Master Casters®, 3/8w x 1h Stem, Soft Tread, 5/Set Contemporary design, strength and performance make these replacement casters an excellent choice for office and home furnishings. With appropriate stems and fasteners, each caster can be used on wood, metal and tubular metal chairs, furniture and other equipment. All casters carry the manufacturer’s guarantee against defects in material and workmanship. For light to medium duty. Wheels rotate independently.