aliber water meter, small caliber water meter.Water meters with nominal caliber 50mm and below are usually called small caliber water meters, and those above nominal caliber 50mm are called large caliber water meters. These two kinds of water meters are sometimes called civil water meters and industrial water meters. At the same time, this method can also be distinguished from the form of shell connection of water meters. The water meters of nominal 50mm and below are connected by screw thread,