Sep 10, 2021 · GLASS STORAGE BOTTLES: These PYREX round media borosilicate glass storage bottles with caps are ideal scientific equipment for mixing and sampling in labs, schools, and for STEM activities. SAFE, DURABLE & LEAKPROOF: Offering superior heat and chemical resistance, the glass bottle storage caps are linerless, one-piece polypropylene plug seal caps with drip free pouring rings.