Hex. Head Bolt & Nut - M16 X 50 Mm Of Product Grade 'C',M.S. Black. Matl.& Specn : Is: 1 363 (Part - 1) / 2023 (6Th Rev.) And Is: 1363 (Part - 3) / 2018 (5Th. Rev.) , Property Class 4.6 For Bolt An D Property Class 5 For Nut [ Warranty Period: 30 Months After The Date Of Delivery ] ]