Made of plastic, good toughness, strong anti-aging ability, plating on the surface of the screw, corrosion resistance. Featuring with star shape knurled knobs, this allows for easy installing, using and disassembling, save time and energy! This plastic hand knob screw is easy to install and remove and does not require any tools. Features - Color: Black. - Material: Plastic. - Size: 3.00 x 3.00 x 2.00cm/ 1.18 x 1.18 x 0.79 inch. - Stars knob, universally fit and can be used for most types of machine tools, this kit can definitely meet all your daily needs. - This knob are special star shape design, great for comfortable hand grip. - Thread clamping knob black plastic hand knob star shape knob handle for machine tool. - Star shape hand knobs black plastic screw-on handle clamping knob for mechanical equipment, instrument and apparatus. - , not easy to break, ensuring long-standing using! Also, they are thick enough to give you a firm and comfortable grip. Package list: 12 knobs