The Female Coupling Will Only Connect To A Male 1 1/2 NH / NSTThe Male Coupling Will Only Connect To A Male 1 1/2 NH / NSTWorking Pressure - 30 psiWorking Temperature - 140 degrees F to -5 degrees FVacuum Rating - 29 HgHose Color - White and ClearDurable PVC hard suction hose. Clear side wall allows visual check of water flow. External helix ribbing with smooth interior surface for maximum flow while drafting. The anodized aluminum hose couplings are expansion ring and they are not field repairable.All hoses are vacuum tested before shipment.1 1/2" Hose Male CouplingsInside diameter of a male coupling - 1 1/2" inchesOutside diameter of a male NH / NST coupling - 1.99 inches (9 Threads per inch)Outside diameter a male NPSH or NPT coupling - 1.87 inches (11.5 Threads per inch)May be used on floating strainers or below the ground holding tanks.Warning - Not intended for hydrant pressure or head pressure from an above ground holding tanksThe most common thread type in use by fire departments today is NST or National Standard Thread. NST also goes by the initials NH or National Hose. It can even be referred to as NHT or National Hose Thread but NST or NH is more common these days. NH = NSTWARNING: This product contains a chemical known to the State of California to cause birth defects or other reproductive harm. Do not use in connection with drinking water. Wash hands after handling.