metal button: 1), Material: zinc alloy 2), Color: Anti-brass,gun-metal etc 3), Size: 17,18,2.0mm 4), accept OE M 2012 metal buttonNote ... , electrophoresis, organic, kirsite / zinc alloy, rust proofing,1) High quality material2) Professional workmanship.3) Well touch and good looking4) Customized designs or size are ...