No external fasteners visible beautiful finished appearance no screw heads, etc. Anodized satin finish rails & steps. High-strength 6063-T6 aluminum material. Black powder-coated polyester finish on top cap and retainer pieces. When placed in position, ladder is positively restrained from sliding, dropping or rotating. Retainer bracket eliminates sliding. No-mar bumper pads on bottom of rails. All parts finished to avoid snagging on clothing, and eliminate any physical danger of cutting or scratching.