Upper Top Basket for Fleck, Clack, and Autotrol Valves which installs on the bottom of control valves to help prevent media getting pushed into plumbing due to pressure bursts or incorrect plumbing. Used for 1.05" Diameter Distributor tubes. Twist-On Style - The twist-on basket has tabs that lock into place when the basket is inserted and twisted. Some older baskets only pushed in and don't have the tabs that allow it to be twisted and locked into place. The Top Distributor Basket is a twist on style for Fleck, Clack, and Autotrol valves that fits a standard riser tube of 1.05" diameter. This top distributor basket is designed to prevent any of the media from exiting your mineral tank.