The Hillman Group 44590 Full Threaded Hex Cap Screw Zinc Metric M12-1.75 X 100, 6-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