The rubber grommets with a threaded section, when you tighten the screw expands and tightens itself into the hole, without the need of a bolt on the other end of the screw The rubber bungs slide into holes perfectly and when you tighten the bolts they squash up in holes to make a good tighten fit Make from Stainless steels and rubber, strong and Enduring Great for break or old toilet hinges. Fit for most standard toilet with top fix hinge Top Fix: you can using a screwdriver to push it down from base. Save time and effort, Manufacturer: Woedpez