Durable MaterialFitness Bearing Pulley is made of high quality nylon, with steel bearing, durable and wear resistant. Fitness Wheel ReplacementNylon Pulley Wheels are Superb replacements for gym equipment and garage door pulley system, easy to replace. Universal Bearing Pulley WheelUniversal Pulley Wheel hole inner diameter: 10mm, suitable for most gym equipment, home gyms, commercial or person use. FeaturesNylon bearing pulley wheel, low noise, stable performance, and high load capacity. Small friction to ensure easy movement. Easy to InstallGym Bearing Pulley Wheel is lightweight, and it is easy to install. Specification: Material: Nylon, Metal Size Chart: Inner Hole Diameter: 1cm Package Includes: 1 Piece Fitness Bearing Pulley Note: Please allow slightly errors due to manual measurement and different monitors.