Abstract: Disclosed is an adjustable sealing device for sealably receiving a flexible receptacle, including a wall having an aperture disposed therethrough and a gate for closing variable portions of the aperture and having a recess adapted to traverse the aperture to form a variable size opening through the device, the opening being effective to receive a receptacle therethrough and being sealable by the receptacle. The device is adapted to form a seal between the gate and the wall and to guide the gate. Also disclosed are improvements in known apparatus and methods for vacuumizing bags and other receptacles.