These spherical mantles cover both The top and bottom of 1-, 2-, or 3-neck spherical flasks for improved safety and efficiency. The circumferential zipper holds the halves snugly together to prevent heat loss, and the side split in top allows removal without disturbing the flask. Fabric exterior provides effective heating in a space saving configuration. Fabric interior to softly nest glass vessels to reduce the chance of thermal shock and damage to glassware. Ideal for bottom holes, viewing ports, and other tubulations. Maximum heating temperature is 842°F (450°C). Series O supports should be used with this mantle. Supplied with separable 4-ft., 2-wire cord and locking connector. Order controller separately.