Automatic, rapid build-up of pressure saves you having to pump manually. Allows a large pressurised cushion of air to build up quickly and easily for longer working periods whilst maintaining a professional spray pattern. The pivoting compressed air connection valve enables an external compressed air supply to be connected to the sprayer and has an integral, automatic overpressure valve. It fits SOLO pressure sprayer models 456, 457, 458 and 309-FA.