1.Wireless valve control 2.DN15-20 is dry type, DN25 is wet type 3.Supply power by three pieces of 777 dry batteries ... one piece of AAA battery, DN15-DN20 is dry type, DN25 is wet type.2. Reading meter remotely with valve control function, supply ... three pieces of 777 dry batteries, DN15-DN20 is dry type, DN25 is wet type. SYSTEM PROFILE Digital Wireless Water Meter with Valve