These heavy duty round PYREX® bottles are manufactured from low actinic glass for use when storing or transporting light sensitive materials. They include a linerless, one-piece autoclavable orange polypropylene plug seal caps with drip-free pouring rings. New glass bead indicates full capacity line on 100mL through 2 liter size. Bottles have permanent white enamel graduations and marking spots. Caution: Bottles larger than 2L should NOT be used with bottle top filter units, or in other applications involving vacuum pressure, as breakage may occur. DO NOT tighten caps immediately after autoclaving as the vacuum resulting from cooling can cause breakage. A vented cap is NOT recommended for use on the 5L and 10L bottle. A wide range of optional caps are available for these bottles (see B5430).