MATERIALS -- These adhesive casters are made of strong ABS material, sturdy and durable, which is firm and wear-resistant to use for a long time, and they can move heavy objects easily without pressure.ore purchasing. [EASY TO INSTALL] -- You just need to stick the casters to the bottom of the object with the included self-adhesive tape without drilling holes. [UNIQUE DESIGN] -- The rolling caster pulley with round edges, no burrs, no cuts. Caster rotation and precision ball bearings in the shaft make rolling easier. These spare casters allow you to roll smoothly and quietly without making harsh noises, and ensure that you don't scratch or leave marks on any surface. [WIDE APPLICATIONS] -- These adhesive casters are easier for you to push cloth storage boxes bins, shoe racks, book storage boxes, dust bin boxes, trash cans, customized baby toy cars, small appliances, etc. [QUANTITY&SIZE] -- You'll get 8pcs mini swivel caster wheels and 8pcs double sided tapes as a set. The size of the storage box casters is about 3x2cm/1.18x0.79in. Please kindly check the size details.