Preferred for belts and many other projects these are heavy- duty, four part, durable, button type snaps that will last for years of normal use. Their sturdy socket construction assures a firm grip. They have 5/16" (8mm) posts for 8 to 10 oz. (3.2 to 4.0 mm) thick leather. To set these snaps you will need TLF #8058-00 Snap Setter and TLF #8056-00 Snap & Rivet Anvil or #8105-00 TLF Snap-All/ Rivet Setter Set which are sold separately