The threaded stem caster wheels are designed for replacing old and broken wheels on desks, storage racks, chairs, lockers, shoe racks, bookshelves, and other furniture. Widely used in homes, offices, libraries, bars, shops, etc.AdvantageThe threaded casters are made of PA, which is wear-resistant and pressure-resistant, with high hardness and greater load-bearing capacity, ensuring smooth and safe movement. The thickened carbon steel bracket is chrome-plated on the surface to prevent rust and corrosion.Built-in balls, 360-degree flexible rotation, smooth and quiet.InstructionThreaded design, with nut and wrench, easy to install on furniture, can be used to replace old casters. Suitable for smooth tile floors and rough floors. (2mm/0.08" thin and opening mouth is wrench suitable for screw fixing nut installation)Note: 1. Please note that the load capacity of 4 wheels can only be calculated as the load capacity of 3 wheels. Because the road surface is uneven, the force on the 4 wheels may be uneven. 2. Please measure the size of the shelf bolt-hole before your purchase.