Specifications: A variety of Immersion Well Photochemical Reactors are available for the synthetic photochemist engaged in synthesis employing halogenation, exidation, or degradation methods. The reactors are designed to be efficient and include provision for irradiation by low or medium pressure mercury lamps. Double-walled immersion wells (in quartz or borosilicate glass) permit water cooling of lamps or filtering of excitation radiation. Various reaction flasks enable irradiations to be conducted under anaerobic conditions at low or constant temperature.