Oxygen Enterprises, Ltd. was established 1995 with a primary goal of developing instruments for biomedical research and industry. We are focusing on the optical method for oxygen (O2) measurements in biological systems based on phosphorescence quenching. The phosphorescence quenching method is non-invasive, except for special molecular probes, which are added directly to the measurement medium. Our products include a family of unique phosphorescent probes (Oxyphors), which enable fast, selective, absolute oxygen measurements in biological tissues in vivo. Oxygen Enterprises also features versatile phosphorescence lifetime measurement instruments (Oxyled's), optimized specifically for oxygen measurements in the physiological range.