Two functions in one great piece of hardware!
The Ball Lock QD Adjustable Pressure Valve W/Gauge relieves pressure while filtering from one keg to another. At the same time it gives you the ability to read the pressure in the receiving keg.
Note: You need to wind/unwind the end of the valve to adjust the pressure. Wrap a towel around the end piece (about 1/4 in) and clamp down on it while twisting the wrench fitting on the bottom (closest end to the Gas In QD) to loosen it. Then finger tighten or loosen to desired pressure.
Gauge reads 0 - 15 psi