This a pressure reducer used for if you need a higher pressure due to having a longer distance going from your hose bib to your plants, or if your water supply is going up so you need a little extra pressure to bring it up vertically.
Blumat systems need low pressure, much less than comes from normal house water connections. Some of our kits include a pressure reducer but if you'd like to install the other ones or the separate components to a home water system, you'll need one of these Pressure Reducers.
In gravity systems you'll also need one if your storage tank is high uphill. In Grow Rooms and Greenhouses with a reservoir for mixing nutrients, you can connect a small pressure pump to this and automatically feed your plants when you water. On one side it adapts to a 3/4" male hose thread and on the other directly to the Blumat 8 mm supply tube.
For BluSoak Systems, use a our .5bar Pressure Reducer (7psi) as our BluSoak doesn't like pressure over 10psi and can even split. Or use one of these and a flow restrictor alternatively.