Abstract: A tamper-proof security system component allowing a security device with a tamper detection switch to be mounted on an irregular surface. The component includes a rear housing portion, which is mounted on a surface and its actuating surface adjusted, and a front housing portion affixed to the rear housing portion, which contains a security device such as a key pad. When the front housing portion is mated to the rear housing portion by an installer, a tamper detection switch which protrudes from the front housing portion is aligned with the actuating surface in the rear housing portion. In order to adjust the actuating surface, the actuating surface is located on a pivotal arm with a threaded aperture and a set screw disposed within the threaded aperture is turned causing the pivotal arm to move and the location of the actuating surface to be optimized.