EASY TO USE: Put these toilet seat screws in the toilet mounting holes. The rubber grommets have a threaded section so you can just push them into the holes in the top of the toilet pan and when you tighten the screw it expands and tightens itself into the hole, without the need of a bolt on the other end of the screw. Convenience and saving time. FOR YOUR SHAKYY TOILET SEATS: Please use these Ancable toilet seat fixing screws to replace the useless plastic inserts supplied with a new top fix seat. Fits for most UK standard size toilet seats with top fix hinge. Suitable for 14 - 16mm hole ONCE AND FOR ALL: You only need to install the toilet cover and the toilet seat hinges top fixings once. There is no need to worry about toilet problems anymore, they can be used for several years! QUALITY MATERIAL: Composed of rubber and metal, the rubber jacket is more resistant to dirt and wear, has a better expansion effect, and is not easy to break. Metal screws are less prone to rust under the protection of rubber and can be used for a longer time.