... steel,stainless steel,copper Can be flat head and csk head Body with or without knurl Rivet NutSize:M3-M12Material: ... carbon steel,stainless steel,copperCan be flat head and csk headBody with or without knurl Surface treatment:Plain, Black, ... steel -----resistant to corrosion and temperature, Rivet nut head style----flat head, countersunk head, reduced head Flat Head Knurled Rivet Nut