INPUT SIGNAL: Water level gauge 0~190ohm (European Standard), Operating Voltage: 9-32V(12V/24V). USE: This water gauge is compatible for all kinds of water level sensors with the same signal and shows the liquid level of the water tank. PREMIUM MATERIALS: The water tank level indicator is made of 316 stainless steel, good quality ABS and PC materials, water resistant and anti-fog, flame retardant. Use the principle of moving magnet to drive the needle, with good resistance and anti-vibration. INSTALLATION DIAMETER: 52mm or 2-1/16'' water tank gauges. Indication Range: E-1/2-F (E means vacuum, 1/2 means half water, F means full water). Installation diameter: 52mm or 2-1/16'' Indication range: E-1/2-F (E means vacuum, 1/2 means half water, F means full water) Input signal: 0~190ohm (European standard) Operating Voltage: 9-32V(12V/24V) Backlight: Red Operating mode: LCD display, stepper motor Package includes:1x Water level indicator 1x Multiple Plug 1x Installation Instructions..Items from Sheng Xinshun's shop