MATTE BLACK FINISH: The rollator plastic knob features a durable matte black coating that resists wear over time and provides a textured grip for secure handling. 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, contributing to a stable and safe walking experience. EASY TO USE: Walker accessories require simple assembly and can be attached quickly in just a few minutes. CONTENTS: The package includes 2 plastic knobs and 2 bolts with washers. These components are designed for easy hand assembly. Please review the product title and description for complete details on size, dimensions, features, and specifications to ensure compatibility with your needs. We aim for your complete satisfaction. For any questions regarding the product, please reach out through Amazon's messaging system. Thank you for selecting this product. We hope it meets your expectations.