G.R.I.'s Roller Ball switch is a unique application of the magnetic reed, combining into a single package mechanical plunger action and the reliability of a hermetically sealed switch. The ball plunger can be activated from any direction within 360 degrees, using a sliding motion such as that produced by the opening or closing of a door or window into its frame. But they also have been used very effectively as an interior trap device by mounting on a flat surface, such as a display table, and placing the protected object directly on the switch to conceal and actuate the roller ball. G.R.I. Roller Ball switches can work when nothing else will.