Material: Made of cold-rolled steel and high-strength nylon, the surface is treated with advanced spray, wear-resistant and durable for long-term use. Self-cleaning function: Each activity automatically cleans and refuses dust accumulation and stagnation, which effectively prevents dust from entering and is more durable. Mute: Nylon wheel, mute works well, with these furniture casters, you can open and close the door comfortably and quietly. Application: The versatile sliding wheels are ideal for doors, drawers, windows, cabinets, wardrobes, closets and more, for a variety of indoor scenes. Size: Roller diameter about 30 mm / 1.18 inches, mounting size about 65 x 27 mm / 2.56 x 1.06 inches, hole diameter about 5 mm / 0.19 inches, set of 4 furniture casters, meets your needs.