A device, and a container having such a device, is provided for filling the container with a predetermined weight of fluid. The device includes an input portion with a throat and a shoulder for introducing fluid into the container. A shut-off mechanism has a shut-off member and a control port. A control mechanism maintains one or more spheres in an inline configuration with the shut-off member such that fluid flow is permitted between the shut-off member and the control port as the device is disposed in an open configuration. A stabilizer is provided for each of the one or more spheres to maintain the inline configuration. As the fluid contained in the container reaches a predetermined weight, a displacer becomes buoyant and lifts the stabilizers with a destabilizer mechanism, which allows the one or more spheres to move transversely, causing the inline configuration to collapse and allowing the shut-off member to settle against the control port to establish a fluid-tight sealing engagement therewith, whereupon the upper surface is displaced such that a fluid-tight sealing engagement is established between the upper surface and the shoulder, shutting off filling of the container. One or more nudgers may be provided to assist with collapsing of the inline configuration. A method of practicing the invention is also provided.