Abstract: A valve, such as a liquid level sight glass gage valve, has a valve unit and a passageway that extends through the valve unit. The passageway has a stem receiving area, a seal receiving area, and a bonnet receiving area that has a non-circular inner perimeter. A packing assembly is provided to isolate the bonnet receiving area from the fluid path. A bonnet is located within the bonnet receiving areas and has a non-circular outside surface for mating relationship with the non-circular inner perimeter of the valve unit. A valve stem is in sealing relationship with the packing assembly and selectively engages a valve seat. The stem threadably engages the bonnet. A bonnet nut is threadably received on the valve unit for securing the bonnet within the valve unit and allowing axial movement of the bonnet against the packing assembly, thereby effecting compression of the packing.