Medical Oxygen concentrators provide oxygen for patients through the use of Pressure Swing Adsorption (PSA).  Oxygen generating Molecular Sieves are specially designed for this application. Nitrogen is adsorbed into the pores and then desorbed and vented off.  This leaves purified oxygen as the product.  PSA technology is a reliable and economical technique for small to mid-scale oxygen generation.  Molecular sieves for this application can range from 8x12 to 60x80 mesh.  Sieves designed for this application are typically of the 13X or LiX type.