Relieves pressure while filtering from one keg to another while also letting you read the pressure in the receiving keg.
Notes: Gauge reads 0 - 15 psi. You need to twist the end of the valve to adjust the pressure. It sometimes comes threaded all the way on from the manufacturer occasionally. 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.