M8-1.25 x 40mm DIN 7991 Hex Drive Class 10.9 Black Oxide Finish Alloy Steel Flat Socket Cap Screw / HEAD STYLE: C1 HEXAGON HEAD DIAMETER: 15.57 MILLIMETERS MINIMUM AND 16.00 MILLIMETERS MAXIMUM HEAD INSIDE DIAMETER: 7.78 MILLIMETERS MINIMUM AND 8.00 MILLIMETERS MAXIMUM HEAD HEIGHT: 3.2 MILLIMETERS MINIMUM AND 3.5 MILLIMETERS MAXIMUM END ITEM IDENTIFICATION: MRAP-BUFFALO A1 COLOR: BLACK OVERALL MATERIAL: STEEL OVERALL