... and long life small flow gas flow meter (min flow for gas is 15L/hr ) We are QUANZHOU RIXIN FLOW METER ... .B,Flange ,clamp,thread inserted connection etc.C,4~20mA,pulse,0~10V,RS485,HART etc.D,D,anti-interfere, anti ... ~2 years),external power supply of 24VDCOutput forms:4-20mA;pulse,0-10V;RS232/RS485;Hart protocol,GPS.Our digital flow ...