Duotight Flow Stopper Automatic Keg Filler - KL09393The Duotight Flow Stopper is a handy device to use while filling kegs or when transferring between kegs during filtering or after fining. Simply attach the Flow Stopper to the gas post of your keg, then when the keg is full it will automatically cut off flow and prevent excess beer from exiting your gas post and spilling onto the floor. For even better results, we recommend using the Flow Stopper with the BlowTie Spunding Valve. The BlowTie will