Home / Forums / Buying a melodica / Upgrade from Walther P/U 10 / Reply To: Upgrade from Walther P/U 10 Reply To: Upgrade from Walther P/U 10 March 3, 2017 at 11:01 pm #8328 Alan BrintonParticipant One very desirable feature of the Pro is the screw-off air vent.
