Key Features1. Smooth Sliding: Wheels Provide Smooth, Effortless Sliding For Windows.2. Durable Construction: Made From High-Quality Materials, Such As Stainless Steel Or Nylon.3. Easy Installation: Simple Installation Process, Often With Screws Or Clips.4. Low Maintenance: Easy To Clean And Maintain, With Minimal Parts To Replace.Stainless Steel, Nylon, Or Other Durable Materials.