Abstract: A side pocket mandrel has an elongated receptacle in the side pocket, parallel with the main bore. A lateral side port communicates the receptacle with the exterior of the side pocket of the mandrel. A flow control assembly includes a sliding sleeve valve and a control valve, both designed to be removable from the receptacle. The sleeve valve is movable within the receptacle between a closed position and an open position relative to the side port, and includes collet fingers having outwardly projecting latching lugs for engagement in a receptacle latching recess in the closed position. The bore of the receptacle is slightly larger below the latching recess than it is above the recess, so that limited inward movement of the latching lugs, restrained by an insert within the sleeve valve, will permit movement of the valve downward to the open position but will not allow movement of the valve upward from the closed position, so long as the insert is in place.