This is a gauge block that goes between the coupling block on the end of the hose and the PX7 or GX7 gun. It allows the installer to see the pressure balance as it's being installed right at the gun without having to go all the way back to the rig to see if you have a pressure imbalance. This particular block allows either the PX7 or Gx7 gun to be attached to the PMC coupling block. To go from a Graco or Carlisle coupling block to a PX7 or GX7, use part number AD001.
