Material And Size The Parts Of The Toilet Are Made Of Plastic, Rubber And Sturdy 304 Stainless Steel To Avoid The Problem Of Screw Bits. Expansion Ball Diameter: Approx. 1.7 Cm / 0.67 Inch (Unexpanded State). Length: Approx. 4Cm / 1.57 Inch.Suitable For 14 - 16Mm Hole Top Seat FixingIdeal For Broken Or Old Toilet Seat Hinges. Fits Most Standard Toilet Seats With Top Hinge Easy To InstallThe Rubber Grommets In The Kit Have A Threaded Section For You To Press Them Into The Holes At The Top Of The Toilet Bowl. When You Tighten The Screw, It Expands And Tightens Into The Hole A Bolt At The Other End Of The Screw. , Rustproof WasherComes With 8 Soft Plastic Washers.Plastic Washers Do Not Rust, They Are Better Than Metal Or Other Bathroom Fixture Top Fixings.When You Tighten The Bolts, The Washers Sink Into The Holes And You Be Careful Not To Overtighten The Bolt As It Goes Through The Washer. Package Includes 4X Black Rubber Tube Nut, 4X Silver Steel Screw, 4X Small Washers In Silver Metal And 4X Large White Abs Plastic Washers, Enough For Your Replacement