These are star screw nuts. Made of high-quality ABS, durable and long life, easy to replace, easy to operate, ergonomically designed to allow easy adjustment and tightening without the use of additional tools, and has maximum control and flexibility, widely used in machinery and equipment, industrial equipment. Features - Color: Black. - Material: ABS. - Size: 3.00X3.00X1.50cm/ 1.18X1.18X0.59inch. - Thread clamping knob black plastic hand knob star shape knob handle for machine tool. - These screw nuts are made of ABS materials for durability and long service life. - Great for comfortable hand grip, accord with ergonomic design and plays a non-slips effect without scratching your hands. - Universally fit and can be widely used for most types of machine tools. - Widely used for mechanical equipment, apparatus, instrument, food and industry equipment.