Edelbrock Exhaust Header Bolt Kit #8543 contains a set of 12 high-quality black oxide steel flanged bolts for universal applications that require a M8-1.25 thread pitch and 25mm length. These header bolts feature a combination hex-Allen head that allows you to use a 10mm combination wrench. The flange design helps to distribute pressure and eliminates the need for separate washers. The black oxide finish provides a nice aesthetic look with mild resistance to corrosion in dry environments.