Abstract: A tap incorporating a tap body and a tap top assembly having an inner end in sealing engagement with the valve seat within the tap body and having a pair of ceramic discs in a housing within the tap top assembly for controlling fluid flow, and operable by a spindle. The control valve is received within a closure member, one end of which is externally threaded at so as to be screwed within an access opening to the tap body with the other end being internally threaded at to receive an externally threaded adjustment nut surrounding the spindle and cooperating with the control valve, whereby, when the tap top assembly is screwed into the tap body, the adjustment nut is operable to move said control means axially into tight engagement with the valve seat. The externally threaded adjustment nut carries a lock nut adapted to engage the closure member and lock the adjustment nut relative thereto.