These are some , which are made from stainless steel and has a longer service life. The simple structure design minimizes moving parts, much easier for you to install and disassemble. Widely used in various engineering machinery and equipment, used for locking and fixing between optical shaft fixture bases, etc. Features - ColorSilver -Material: Stainless Steel. - Size: 5.90X2.50X1.00cm/2.32X0.98X0.39in - Stainless steel plunger body, pin and pull ring for safety and durability, can be used for long period. - Good for many fields of equipment such as lubricating, trucks, film and television industry, audio, workshop machine tool production. - This is small size and portable, convenient and easy to take to any places you need. - With its simple but stable structure and excellent texture, for you to use rest assured. - These knob plungers minimizes moving parts, much easier for you to install and disassemble. Package list: 4 x Spring Plungers with Pulls Ring (LHFSS-10-1.5-6- Stainless Steel Head)