Material: rubber (expandable ball) / ABS plastic (round cards) / stainless steel (screws) Size: Expansion ball diameter: 1.8cm / 0.7 inch (unexpanded state) Length: 4cm / 1.57 inch. Fits 14-16mm hole for 2 toilet seats Universal fit : Fits most standard toilet seats with top hinge Easy to install : Grommets Kit rubber have a threaded section so you can just push them through the holes at the top of the toilet bowl and when you tighten the screw it expands and tightens in the hole, without the need for a bolt to the other end of the screw Wide applications: ideal for broken or old toilet seat hinges