Non-Sterile, precision molded, Conical bottom Test tubes for general purpose laboratory work. Polystyrene tubes provide clarity and are appropriate for use with mild acidic (except oxidizing acids) or alkali solutions, alcohols (except higher alcohols) and salt. Polypropylene tubes are more chemically resistant and are appropriate for use with organic solvents and stronger acids (except oxidizing acids), alkalis, alcohols, chlorinated & aromatic hydrocarbons (except xylene) and ketones.