MATTE BLACK FINISH: The rollator plastic knob features a durable matte black coating that resists wear over time and provides a secure grip. ZINC-PLATED STEEL: Bolts and washers for walker accessories are constructed from zinc-plated steel to resist moisture and withstand outdoor conditions. NON-SLIP: Rollator accessories are designed to remain secure and prevent slipping, enhancing the walker's stability and safety. EASY TO USE: Walker accessories require simple assembly and can be attached in minutes. INCLUDED: The package includes 2 plastic knobs and 2 bolts with washers, all of which can be easily assembled by hand. Please review the product title and description for detailed information on dimensions and specifications to ensure compatibility. For any questions or concerns, feel free to reach out for assistance. Thank you for selecting this product.