KOOLER KEG BALL BEER TAP KNOB / HANDLE. KOOLER KEG KNOBS HAVE A SQUARE THREAD HOLE AND WERE USED ONLY WITH A KOOLER KEG KEGLINE SYSTEM WHICH MAKES THEM USUALLY RARER AND HARDER TO FIND THEN NORMAL STYLE BALL KNOBS. TAP KNOB IS IN GOOD CONDITION WITH SOME WEAR. WILLAM PETER B REWERY – BREWING CO. UNION CITY NJ – NEW JERSEY.