These header holts feature a 3/8'' hex head and come with AN-style washers. They are designed for quick and easy installation of headers and are heat-treated for extra strength. The washer faced, smaller than standard hex head is ideal for tight spaces and are grade-5 with a 7/16" hex head. Both the socket-head and hex-head styles are available. The socket-head bolts are made from stronger grade-8 steel for ruggedness and are great for difficult-to-reach spots. Both styles have a protective black oxide finish and are sold as a set of 16.