Each roller wheel in this pack has a diameter of 25 mm (1 inch), making them suitable for standard sliding door systems. These rollers are typically made from high-quality materials such as iron or POM (Polyoxymethylene) for the wheel with brass frames or stainless steel screws, ensuring longevity and resistance to corrosion. The robust construction provides smooth, noiseless rolling that aids easy door movement without causing damage to door tracks.