Blue Sea 1842 M2 OLED Digital Bilge Meter [1842]1842 M2 OLED Digital Bilge Meter The M2 Organic LED Digital Monitor measures essential electrical system parameters with adjustable alarms and an auto dimming display. The M2 Monitors include a MOSFET External Circuit Relay (ECR) which can be used to control external circuits based on any value measured by the M2. Features: Auto dimming, bright Organic LED display is easy to read 80dB alarm on all models Isolated 500mA MOSFET relay Bilge float switch