Abstract: Apparatus including the combination of a nozzle adapted for connection to a source of fluid under pressure and having a port for discharging a jet fluid axially of the port and a wall mounted in spaced relation to the port and generally across its axis and having an opening dimensioned for passage therethrough of the jet when the port and wall opening are in registration, and wherein the wall and nozzle are mounted for relative displacement for moving the port and opening into and out of registration; and manually engageable means for effecting such relative displacement. Additionally a housing is provided around the nozzle to form a relatively enlarged, reduced pressure, fluid collection chamber for fluid deflected by the wall in the misaligned "shutoff" position of the device.