The Krueger Therma Level Gauge For 57-16N606 is a liquid-filled thermometer that indicates temperature for steam heating systems. It has a 6 inch scale, 1/2 inch NPT bottom connection, and temperature range of 30 to 250 degrees Fahrenheit. This gauge helps monitor boiler water temperature to ensure efficient steam production. Made of steel with a black painted case, it has clear glass, red organic liquid, and is 9 inches tall. From Krueger, this quality gauge is designed for long life.