If you're into DIY projects or need to make custom buttons for events, this ChiButtons 200-set kit is absolutely perfect. Each set includes the metal upper shell, protective Mylar sheet, and pre-pinned metal back with safety pin - everything you need to make professional-looking pin badges. The 37mm size (metric system) is ideal for most designs, and the round shape is classic and versatile. The metal components are durable and won't break easily, and the safety pins are already attached to the backs, saving you time. They work with ChiButtons button makers perfectly, but should be compatible with most standard 37mm button press machines. The quality is solid - these aren't flimsy components that'll fall apart. Whether you're making buttons for school events, political campaigns, business promotions, or just for fun with friends, this bulk pack gives you plenty to work with. The whole process takes seconds once you get the hang of it, and the results look store-bought. Seriously, if you need to make a bunch of custom buttons quickly and affordably, this 200-set kit delivers exactly what you need. It's way cheaper than ordering custom buttons elsewhere, and you get the satisfaction of making them yourself!