For Portable Airless Spraying of Skim Coat Materials, Architectural Coatings and Paints 3300 psi (228 bar, 22.8 MPa) Maximum Working Pressure This model is replaced by #258729 The essential difference between series A & B is new control board and the heavy duty prime valve on B. Many parts cross reference with the UltraMax II 695 & 795 series of sprayers