Complements all types of office and home-office furniture 2in. diameter dual wheels provide maximum mobility and smooth quiet rolling on light-duty to medium-duty applications. Use soft wheels on hard floors and chair mats. Weight rating is 100 lbs. per caster. Casters include 7/16in. x 7/8in. B stems and 3/8in. x 1in. K stems. Master Caster Duet Casters, 2in. Diameter, B/K Stems, Soft Wheels, Black is one of many available through Office Depot. Made by Master Caster.