... brass, aluminium 3.zinc plated,hdg,black carriage bolt Itemcarriage boltMaterial of carriage boltCarbon steel(,Q235,C1010,C1020,C1040,10b21,etc ... 8,grade10.9,grade12.9ANSI,ASTM:grade2,grade5 grade8Finishing of carriage boltColoured zinc-plated(galvanized,can be white,blue,yellow ... Chrome-plated,Tin-plated,DacrometPassivation,Dacroblack,QPQ,Polished,MattSize of carriage boltM3 M4 M5 M6 M8 M10 M12 M14 ...