1/4-20 x1/2" Button Head Torx Security Machine Screw Bolt Screws Stainless Steel Tamper Resistant, Qty 10. We supply the toughest and most durable security screws around. They are available in both sheet metal and machine threads.Our tamper resistant screws provide a higher level of security for you with their drive design, which prevents removal with normal screw drivers. We offer a large number of head-styles, driver kits and matching tools for installation and removal. These tamper resistant screws are suitable for providing tamperproof fastening for a wide range of applications. Tamper pruf resistant screws will allow you to save thousands of dollars by protecting you from such things as theft, vandalism, corrosion, and tampering.