FOR CARTS Smooth-rolling replacements for carts, dollies and poly box trucks. Swivel casters have hardened double-ball raceways. Non-marking and quiet. Rolls easily on tile and linoleum. Bolt hole spacing: 1 3/4 x 3". ULINE offers over 37,500 boxes, plastic poly bags, mailing tubes, warehouse supplies and bubble wrap for your storage, packaging, or shipping supplies.