Article 98(1) and (2) of Council Directive 2006/112/EC of 28 November 2006 on the common system of value added tax, as amended by Council Directive 2006/138/EC of 19 December 2006, and Annex III, points 3 and 4, of that directive do not preclude a national provision by which a reduced rate of value added tax is not applied to the supply and/or hire of oxygen concentrators like those at issue in the main proceedings, inasmuch as those appliances neither constitute pharmaceutical products within the meaning of Annex III, point 3, of Directive 2006/112, as amended, nor are for the exclusive use of the disabled within the meaning of point 4 of that annex, which it is for the referring court to ascertain. The principle of fiscal neutrality may not be interpreted as authorising the thwarting of the respective ambits of the categories set out in Annex III, points 3 and 4, of Directive 2006/112, as amended, by granting a reduced rate of value added tax for the supply and/or hire of devices that do not satisfy the definitions laid down in those points.