These 4-hole buttons come with a needle and 3 metres of thread for secure fastening. Metal is hands down the best material because animal horn or ivory would not be strong enough therefore it would not be fit for purpose. These buttons have been specially designed for braces. Buttons have been designed to be 18 mms in diameter for the optimum life of leather tabs. And most importantly: button shape and thickness have been considered for optimum comfort. The wording has been embossed so it will not wear away with time and button colour gives an authentic look.