According to the "Model In A Bottle" website, the ingredients for Model In A Bottle Original Formula are: SD Alcohol 408, Purified Water, Isopentildyal[sic], Acrylates / Octocrylamide[sic], Copolymer, Aloe Barbadensis (Aloe Vera), Biosaccharide Gum, Propylaparden[sic], Methylaparaben[sic], Diazoilinyl[sic], and light Fragrance (quite a few spelling errors in the chemical names on that site, I must say).
From what I know, octylacrylamide/acrylates are the active ingredients found in hair spray formulations as fixative resins. SD Alcohol 408, purified water and isopentyldiol are solvents. Propylparaben, methylparaben and diazolidinyl urea are preservatives.