Pyrex heavy-duty round media storage bottles can be used for storage as well as for mixing and sampling. These media storage bottles Include linerless one-piece autoclavable orange PP plug-seal caps with drip-free pouring rings. Optional red PBTP caps and red ETfE pouring rings are available separately for dry heat sterilization (180C).Pyrex round media storage bottles are made of borosilicate glass with permanent white enamel graduations and marking spots.Caution Bottles larger than 2 L 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 wide range of optional caps are available for these bottlesVented membrane cap with 0.22 mum PTfE hydrophobic membraneRed PBT (polybutylene terephthalate) solid caps and ETfE pouring rings for dry heat sterilization (180C)PBT caps with silicone septa for s