shoulder screws: 1Standard:by clients 2Grade:4.6, 5.6, 8. ... speed railway and now they are being used. We exported to world markets, such as U.S.A., Canada, Cuba, ... , Japan, Singapore, Malaysia and Africa and so on.Pictures related to the product.1. certificate2.Various honorary certificate3. we also supply ... equipmentsWorkshop Welcome your visit! Railway fasteners AS standard hex head shoulder screws