20 Star Knob Screws M6 40mm, Threaded Plastic Clamping Knobs for Machinery and Industrial Equipment (Black) HIGH QUALITY: The M6 star knob screw is made of high-quality plastic, providing durability and impact resistance for a long service life. The screws are made of high-quality carbon steel, are highly hardened, rust-proof, firm, and durable. Package Contents: 20 x Star Handle Screws. Color: Black. Head diameter is 30 mm. Screw length: 40 mm. The thumbscrew fits most machines. EASY TO USE: The star knob's plastic handle has a comfortable grip and can be attached and installed by hand without other tools, and can be turned directly by hand. The design makes it easy to install, disassemble, and adjust. STAR-SHAPED DESIGN: The M6 thumbscrew has a star-shaped design that provides a comfortable grip and can easily tighten the screw manually without slipping, and has no burred spiral. Very good for fastening, not only neat, but also practical. WIDE RANGE OF APPLICATIONS: The clamping knob screw is used to fasten and secure components, devices, and operating parts to the machine. Fits most machines and devices. For example, mechanical equipment, instruments, food and industrial equipment, household appliances.