The Plumbing Kit is an accessory item we offer for Air Knives that are 24" (610mm) in length or longer. Any Air Knife that is 24" (610mm) or longer should be plumbed with compressed air fed into two or three inlets, depending on the length. The Plumbing Kit will connect the necessary air inlets of the knife with the properly sized hose and fittings. It also results in only one individual connection you will have to supply your air into, simplifying the installation of the knife. You can choose to install the plumbing kit or have EXAIR install it at the factory. The Plumbing Kit is to help ease the installation of the longer Air Knives.