Greystone CMD5B4000-MOD Carbon Monoxide(CO) Detector uses an electrochemical sensor to monitor the carbon monoxide level and outputs a field-selectable 4-20 mA, 0-5, or 0-10 Vdc. The sensing range and output may be scaled to either 100, 150, 300, 400 or 500 ppm via the onboard menu. A front-panel LCD is standard to ensure easy setup and operation. Other standard features include a backlight for the LCD, a front panel test switch, a status indication, and an alarm buzzer. The test function may also be controlled remotely with a digital input signal.