Hangzhou Yanshan Import & Export Trade Co. ltd. are in Hangzhou.The company specialize in processing and exporting of the instruments. There are producing five kinds products : oval wheel flow meter,glass rotor flow meter and constant flow pump, Rotor wing flow meter, Spiral Rotor flow meter, Rotary piston flow meter ,constant flow pump and so on. with dozens of series production .The products are all passed ISO9001 international quality management system authentication.