Mobility and Daily Living Aids Health & Household, Medical Supplies & Equipment, MJM International, Mobility Aids & Equipment, Mobility Scooters & Accessories, Wheelchairs MJM International R-3TW-RP Replacement Caster Set, 3″ (Pack of 4) Review by RoomPony July 15, 2018 No Comments Product Description Replacement 4″ twin nylon threaded stem casters / set 2-lock 2-nonlock. Manufacturer Contact Information 800-270-6199