Drip Systems use low water pressure to operate efficiently. This two stage assembly reduces the water pressure before filtering it to the drip system. Drip line & conventional drippers emit water from tiny outlets & require filtered water to avoid blockages. Always protect the system by using a filter. Blockages will stop drip line operating. Install from a water source with a pump, directly onto a tap, or along the mainline in the garden but locate "inline & before" the irrigation.Specifications: Pressure Reducer - Inlet: Maximum 8bar (800kPa), Inlet thread size: 3/4" BSP (female), Outlet: 1.8 bar (180kPa), Outlet thread size: 3/4" BSP (male)Filter - Inlet thread size: 1" BSP (male), Outlet: 13mm or 19mm Barbed end.Holman's pressure reducer & filter assembly has it all in one!