Picture of nuts and fasteners; the one nut is in a shallow housing which spins if someone tries to remove it without the correct tooling.
This is a fastening system that looks the same as an existing one but I have made simple changes to the fasteners and the tooling which changes it into a high-security fastening system.
The fastener if sunk below the surface of the component it is securing would be very difficult to remove without the tooling. It has a greater torque rating than an allen pin, has less wear, has a better compression figure, and can be used as a high-security fastener or nut.
Smart-thread.com.uk 