Marine Digital Battery MonitorThe Panther battery gauge allows you to determine the exact amount of charge remaining in your batteries. Designed for permanent mounting the battery gauge will fit into any standard meter cut out, and will work with any standard or deep cycle 12 volt lead acid batteries. LED display meets MIL specifications for heat and vibration resistance.The gauge is internally lit for day or night use. Comes complete with easy to follow instructions for do-it-yourself installations.