A Sensing Edge is a touch sensitive switch that sends a signal to start, stop or reverse a motor-Sensing edges detect obstructions in openings controlled by garage doors, rolling doors, rolling grilles, or gates and provide a signal so that operators can respond appropriately. These edge devices are usually attached to, or are part of, the bottom edge of an upward acting door or grille or the leading and/or trailing edge of a moving gate. When a sensing edge detects an obstruction, it will signal the operator to perform one of the following actions on a door/grille/gate: 1. stop during either a closing or an opening movement, 2. stop and open during a closing movement, or 3. prevent a closing action from an open position. Sensing edges typically are used to protect against entrapment and are often defined in standards, such as the UL 325 Standard for Safety for Door, Drapery, Gate, Louver, and Window Operators and Systems, as being an acceptable means of providing entrapment protection.