DEVICE: Oxus Refurbished Sieve Bed (00867460000120)

A mobile/portable mains electricity (AC-powered) device designed to concentrate oxygen (O2) from ambient air and deliver the concentrated O2, typically through an attached nasal cannula, to a patient requiring oxygen therapy. It processes the air through an internal filtration system, e.g., a molecular sieve (zeolite granules or membranes), having a large total surface area to separate nitrogen (N2) from the air. It typically consists of an air compressor, filters, dual chambers, a reservoir and controls. The O2 concentration is variable depending on the flow rate utilized. It is used in a home, institution, or a vehicle and typically has internal batteries for transportable use.