The Hillman Group 45523 M8-1.25 X 40-Inch Metric Class 8.8 Hex Cap Screw, 14-Pack A common feature on a hex cap screw is a washer surface directly under the head which creates a better seal An alternative for using them without nuts is to install them directly into a compatible internally threaded hole Hex head cap screws come in a variety of sizes, finishes, grades and threads