These heavy duty 5 L PYREX round bottles can be used for storage as well as mixing and sampling. They include a linerless one-piece autoclavable orange polypropylene plug seal GL45 threaded cap with a drip-free pouring ring. Bottles have 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 vented cap is NOT recommended for use on the 5 L bottle for venting during autoclaving. -A wide range of optional caps are available for these bottles -Polypropylene colored caps in a choice of orange green purple red and light gray for ease of sorting and identification. -Vented membrane cap with 0.22 mum PTfE hydrophobic membrane. -Red PBT (polybutylene terephthalate) solid caps and ETfE pouring rings for dry heat sterilization (180C