A device for fastening a barrel of a gas operated soldering gun to a spout of a combustion chamber thereof is disclosed. The light modulator pixel unit includes top, movable and bottom electrodes. The electromagnetic via couples a signal pad on the active face of the integrated circuit chip to the back face of the integrated circuit chip so that the integrated circuit chip can communicate with the second integrated circuit chip while the back face of the integrated circuit chip is adjacent to the active face of the second integrated circuit chip. The back-up mirror method comprises the same back-up mirror, which provides an alternative view of any nearby oncoming cross-traffic for a driver backing up, which view is especially useful when direct views are blocked by an adjacent obstruction. The inputoutput signal control circuit includes a first latch circuit connected to an input section of the first output buffer, a second latch circuit connected to an output section of the second input buffer, and a control switch connected to an input section of the first output buffer and an input section of the second output buffer.