A button head socket cap screw is a type of cap screw with a cylindrical head and hexagonal drive hole. Compared to a standard socket head cap screw, button heads have a lower and wider profile which can be useful when the clamping material is too thin to counter-bore. A button head socket cap screw's large diameter face also helps to distribute force more evenly. Pin In Security Button Head Socket Cap Screws have a traditional Hex drive with tamper-resistant pin added for security. Easy to drive & remove with matching security tool.