Size: Extension Ball Diameter: 1.8 cm (undeployed state). Length : 4cm. White screw size: 4.5x0.5cm. Nylon Extension Nut Size: 3.7 x 1.8cm. Washer diameter: 1.4cm. (The detailed size of each toilet seat nut is in the picture, please measure before purchasing to ensure your toilet seat works well) Excellent material: the stretchy ball is made of black rubber, white screw with solid brass thread inside is made of nylon, long screws and gaskets are made of 304 stainless steel, soft washers are made of ABS plastic. Sturdy and durable, rustproof and corrosion resistant, better than most plastic fasteners. Rustproof Design: Plastic washers won’t rust, better than metal washers. When you tighten the bolts, the washers smash into the holes, you have to be careful not to tighten the bolt so much that it pushes through the washer. The screw has a solid brass thread inside can be anti-slip and anti-rust. Easy to use: Put the bolts into the mounting holes of the toilet. The rubber grommets have a