DURABLE PREMIUM - These knob handles are made of high quality plastic and copper, they are corrosion resistant, have good toughness and impact resistance, and have a long service life. > Star Design - Hex star and inline designs offer comfortable prices. The surface is carefully polished, smooth and burr-free, so it won’t hurt your palm when you hold it. EASY TO USE - Screw design, easy to install, just align the female thread with the screw and twist it hard. They are great accessories to replace old or damaged handles. EASY TO USE - Screw design, easy to install, just align the female thread with the screw and twist it hard. These are great accessories to replace old or damaged handles. You can get - 14 x M8 Black Threaded Clamp Knobs. Internal thread diameter: M8; Head Diameter: 30mm/1.18"; Height: 13mm/0.51".