Adult Percent-O2-Lock air entrainment assembly with humidity cup without mask or oxygen supply tube. The Percent-O2-Lock air entrainment oxygen mask includes a rotating sleeve, opening and closing an air entrainment window. This provides the ability to deliver seven (7) fixed oxygen concentrations to a spontaneously breathing patient. Concentration levels are easily dialed and locked in. The dial-in air entrainment assembly is affixed to a standard aerosol mask. A high humidity adaptor permits use of a nebulizer with mask if prescribed.