The 6″ Grey Ridged Plate Caster is a direct-bolt caster with a 4″ bolt pattern. It can be used with a 1-3/4″ bolt for single 1″ x 1″ tubes or a 2-3/4″ bolt for 1″ x 2″ tubes, along with a Nyloc nut to ensure security and stability. With a one directional weight capacity of 600 lbs. per caster, it is commonly used for carts, mobile flow racks, workstations, etc. The 6″ Grey Swivel Plate Caster is made of durable materials and designed to provide smooth and easy movement.