The Tektronix WFM90D/WFM91D are handheld, multifunction monitors ideally suited to the monitoring needs of field production, equipment installation or any situation where portability and battery operation is required for analysis of analog composite video and 270 Mbps - SDI systems. The combination of features and monitoring modes provided makes these instruments powerful enough to set up, time and troubleshoot complex video and audio systems, combining the power of four separate instruments in the palm of your hand.