Product name Butterfly nut texture of material SS304 SS316 stainless steel,mild steel, Carbon steel,1018,1022,10B21,SCM435,12L14, 1215,4140, 4340, 5120,5140,5145, etc. standard ASME ISO DIN BS Grade A2 A4 or grade 2 5 8 10 Surface plain, zinc Kuyala, yotentha idayaka, Black Oxide yolongedza pulasitiki / katoni