Shanghai Fengxian Zhezhong electronic instrument Co., Ltd. (Shanghai Fengxian Zhezhong Electronic Instrument Factory) is engaged in a long-term development and production of digital meters, optical switches automation equipment, instrument manufacturers specialized . Since 1976, the plant has, the professional development and production of various types of electronic counters, electronic wire-speed, tachometers, timers, infrared media converter, Hall sensors, infrared optical switch, optical encoder, speed, power automatic compensation factor, multifunction power monitoring instrumentation, digital voltmeter, ammeter and more than 20 varieties of 200 kinds of standard electronic products.