Material: The swivel casters are made of soft rubber wheels and TPE material, super quiet, will not disturb anyone when working, high elasticity, 360flexible use. Bearing design: ball bearing, one-piece bearing, steel ball steering design, sealed bearing with low friction resistance, flexible bearing, 360-degree rotation, stable, high temperature resistance, high speed, dustproof and non-stick, and can be used for a long time Built-in silent bearing, very Quiet and durable. It is ideal for all DIY furniture with movable wheels. Suitable for many kinds of floors: Made of soft rubber, soft and will not damage the floor. Rubber casters are elastic, tough and durable. Suitable for all types of floors such as tiles, cement floors, marble, carpets, parquet, etc. Features: No brakes, 360-degree rotation can move freely, and the applicability is stronger. The wheels are made of soft rubber and anti-rust TPE material for strength and durability. Suitable for different floors. Built-in low-noise bearings for quiet movement. Material: soft rubber and TPE black Wheel diameter: 40mm M815mm thread Load capacity 20 kg per wheel. Box Contents 4 x 40mm swivel casters with M8 x 15mm threaded stem