CONSTRUCTION: Made up of 316 grade stainless steel with a polished finish.A layer of rubber on the flat surface of the ball dampens vibrations and rattling noises while your vessel is going. Easy to use: Magnetic ball door stopper holder is designed to be easily adjustable for any mating angle. A strong magnet ball can hold approximately 5 kg. Durable Quality: Magnets are entirely encased in stainless steel to endure the corrosive marine environment and provide long lasting service. Dimensions: All screw holes diameter: 0.2 inch / 5 mm. Package includes: 1 pc MARINE CITY 316 Stainless Steel Strong Magnetic Modern Ball Door Window Stopper. (Screws are not included)