This rig is for testing what water flow you have available at a pressure you will be needing....................I know what the heck does that mean! Let me try again.
When you have a drip system it needs two things to work correctly. Water Flow and Pressure.
Water Flow: This is the amount of water your drip system will use. This is calculated by all your drippers and microsprinklers, anything that lets water out. If you have 100 drippers and each is a 1 GPH then your system uses 100 GPH (Gallons Per Hour)
Pressure: The majority of drip systems work best at 25 PSI. Sometimes with larger systems you might need to bump that up some. This is best left to someone who knows designs (US! We know designs!!)
You hook this test rig up to your water source and close the ball valve off. You then turn on your water source. Now you open the ball valve until the gauge reads the 25 PSI. You then place a 5 gallon bucket under the water flow coming out of the test rig and time how long it takes to fill it to 5 gallons.
After a little math (All explained on the product page) you know EXACTLY how much water you can supply at 25 PSI.
Detailed instructions are on the product page and come with each test rig.