1. Screw Specifications: 3-inch Locking Swivel Caster, 3/8"-16UNC x 1-1/2" (screw diameter 1/2", screw length 1-1/2") threaded rod caster, noiseless caster, 4-wheel set. In addition, we have 2 sets of casters for you to choose from. 2. Stable Structure: The housing is made of heavy-duty steel to withstand high loads, and the maximum load-bearing capacity of the 4-wheel set can reach 600 pounds. The side-locking brake can hold the equipment firmly in place to reduce accidents. 3. Scratch-resistant Thermoplastic Rubber Wheel: Non-toxic and environmentally friendly, resistant to most solvents. Shock-absorbing and buffered, protects the floor, and rolls quietly. 4. Multi-purpose: These casters can be placed on a variety of equipment such as workbenches, instrument cases, art tables, etc. Whatever mobility assistance your workplace needs, our cart wheels can quickly solve it. Equipped with a 360-degree swivel head, the caster can respond instantly to changes in direction.