... BAirproofNo leaking for 3 minutes under 1.5 times max working pressureNominal Flow Rate1. ... entrance, G1.6/2.5/4.0FQ-SR---steel shell, LCD display, right entrance, G1.6/2.5/4.0FQ ... -SB---steel shell, LCD display, left/right entrance, gas leaking alarming port, G1.6/2.5 ... /4.0 Remote Gas Meter G1.6 ...