The Ozma™ PEG-Series 48-Salt Screens are formulated using one of four different Mwt PEG’s; 30%(w/v) PEG-1000, 20%(w/v) PEG-4000, 20%(w/v) PEG-8000, or 10%(w/v) PEG-10,000 plus 48 different salts. These protein crystal growth matrices provide excellent coverage of a broad range of PEG molecular weights (1K to 10K) at known optimal concentrations for protein crystal growth, in combination with 48 different salts. The cationic components of the salts include coverage of Ammonium, Calcium, Lithium, Potassium, Sodium, Magnesium, and Zinc. The anionic components the salts include coverage of Acetate, Chloride, Fluoride, Formate, Iodide, Nitrate, Phosphate (mono- and di-basic), Sulfate, Tartrate, Thiocyanate, Citrate, and Isothiocyanate. These screens can be used in combination buffers covering pH ranges from 2.4 to 11.5 that comprise our pHat Buffer Screen to further expand the crystallization possibilities.