We developed this product to relieve pressure when we transferred or filtered beer from one keg to another. This connects to the keg you are filtering into and has adjustable relief valve for letting pressure off as the keg fills up.
Notes: The very end of the pressure relief valve can be adjusted by unscrewing to adjust the pressure. If tight, and not adjustable by hand, it needs to be loosened with pliers. Wrap a towel around the end piece of the pressure relief valve (about the last 1/4 in) and loosen with pliers. Then finger tighten or loosen to desired pressure.