Material & SizeThe toilet parts are made of plastic, rubber and heavy-duty 304 stainless steel metal to avoid the problem of screw drills. Expansion ball diameter: Approx. 1.7cm (unexpanded state). Length: Approx. 4 cm / 1.57 inch. Suitable for 14 - 16mm hole. Toilet Seat Fixing Top Fix- Ideal for broken or old toilet seat hinges. Fits most standard toilet seats with Top Fix hinge.Easy InstallationThe rubber grommets in the kit have a threaded section so you can simply slide them into the holes at the top of the toilet bowl. As you tighten the screw, it expands and tightens in the hole without the need for a bolt on the other end of the screw. Non-rust Washer There are 8 soft plastic washers included in the package. Plastic washers do not rust. They are better than metal washers or other bathroom faucet top fasteners. As you tighten the bolts, the washers will squeeze into the holes and you must be careful not to overtighten the bolt so that it pushes through the washer. Included4x black rubber hose nut, 4x silver steel screws, 4x small silver metal washers and 4x large white ABS plastic washers, enough for your replacement.