... square head set screw: 1Standard:DIN,GB,ASTM,BS,or by client 2Size:M20*140,M22*130 3Grade:4.6,5. ... .9,12.9 ( General and High strength) >> Surface treatment: plain, black, zinc, electro galvanize, hot dipgalvanization, Dacrotized and so on. >> Certificate ... Ltd.) is specializing in producing railway fasteners. We have certified by ISO9001:2008 Quality Management System and got the Production Permission ...