About this item This toilet fixing kit is made of high quality rubber and stainless steel,which is strong and durable,with good toughness and stable structure. Metal washers are stronger than plastic.And rubber washers can be used anti-slip. The rubber washers are designed to be threaded so you can push them into the hole in the top of the toilet and when you tighten the screw it will expand and screw itself into the hole. Suitable for toilet seats with a bore diameter of 14-16mm. Fits most standard toilet seats with fixed top hinges. There are 10 expansion bolts in the package.