A fixed-location, mains electricity (AC-powered) device used to create and deliver ozone (O3) - also known as trioxygen. It typically produces a high electrical voltage between electrodes, to convert room air, or oxygen (O2) feed gas, into O3 when passed through the electrode gap. It usually includes measuring devices to determine output O3 concentration, and a mechanism to destroy internally the unused ozone; it is typically used at the site of application because it is not possible to store ozone. O3 has been used for various purposes in the laboratory, to disinfect/purify air and water, and in some clinical treatment of diseases.