A small, mains electricity (AC-powered) device intended to hermetically surround a patient's limb for the topical application of oxygen (O2) from a O2 supply, usually humidified, at a pressure slightly greater than atmospheric (e.g., 1 to 2 atm) during hyperbaric oxygen therapy (HBOT). The O2-enriched atmosphere may be raised above normal pressure by the device either continuously or intermittently. The device is typically a rigid plastic shell with electronic controls or a flexible shell connected to controls, tubing, and other accessories. It is typically used to treat skin ulcerations, decubitus ulcers, infected stumps, skin grafts, burns, and frostbite.