Carpet Security System 58 KhzCarpet Security System 58 Khz (Sensormatic Frequency) This hidden, carpet security system, covers a single foot door or a 6 foot double door. The 5 ft security system mat is placed flat on the floor inside the store centered in front of the doorway. A piece of generic carpet is placed over it to hide it. You may substitute your welcome carpet as long as it contains no metal. This carpet over the pad can be removed to clean when necessary. A controller