The SFT Phase Monitor II is a powerful tool for determining the solubility of various compounds and mixtures in supercritical and high-pressure fluids. It provides direct, visual observation of materials under conditions precisely controlled by the researcher. Experiments may be performed in liquids, supercritical carbon dioxide or other liquefied gases. The effect of co-solvents on the solubility of compounds of interest may be investigated as well. The Phase Monitor II allows the user direct observation of the dissolution, precipitation and crystallization of compounds over a wide range of pressures and temperatures. Advanced studies may be done to determine melting point depressions and the degree of polymer swelling in SF CO2 or traditional solvents. Experiments can be performed at pressures up to 10,000 psi and from ambient temperature to 150 C.