Disclosed is a valve having (A) a valve body with an aperture therethrough, a threaded tap crossing the aperture and opening to only one side of the valve body, (B) a tap screw having a head of larger diameter adopted to screw into the threaded tap, where the tap screw has a hole therethrough which aligns with the aperture when the valve is in an opened position and which is at a substantially right angle to said aperture when the valve is in a closed position, and (C) an o-ring fitted under the head of the tap screw which is compressed between the head and the valve body when the valve is in an opened or closed position.
There is provided a pressurized gas tank valve plug which can safely and effectively fit and seal a first pressurized gas tank valve and a second pressurized gas tank valve each valve having a valve stem of differing interior depth.