MATTE BLACK FINISH: The rollator plastic knob features a durable matte black coating that resists wear and provides a textured 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 provide a secure fit to help ensure the walker remains stable and safe during use. 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, designed for easy hand assembly. Please review the product title and description for detailed specifications and dimensions to ensure compatibility with your needs. For any questions regarding the product, please refer to the provided information. Thank you for selecting this product.