Duotight Inline Regulator - 5/16" (8mm)
Constructed out of non-corrosive acetyl, nitrile, and stainless components, you can use this 5/16" OD Duotight Inline Regulator with either gas or liquids, plus it can be secured using the two mounting points.
The maximum inlet pressure is 150 PSI, so it works well to reduce the main water pressure. You may also use this to reduce the CO2 going to your keg. Set your primary regulator to the highest pressure, run the gas line into a manifold, then install one of these Inline Regulators after each manifold. You can adjust the flow manually using the 'T' adjustment knob.
Remember to cut your 5/16" OD (8mm) EVABarrier & Polyethylene Tubing straight so that you get a secure seal that the dual EPDM O-Rings provide.