Abstract: A valve comprising a hollow cylindrical body with a valve opening at one end and a valve seat around the valve opening. A valve member is movable towards and away from the valve seat on a spindle which passes through a spindle opening opposite the valve opening. A handle is provided on the outer end of the valve spindle and has a screw-threaded counterbore which is engageable with a screw-threaded spigot on the outside of the valve around the spindle opening to hold the valve member in the closed position. In this position the end face of the valve member is flush with the outside of the valve around the valve opening. The upper side of the valve member has a screw-threaded counterbore engageable with a screw-threaded spigot on the inside of the valve around the spindle opening to hold the valve in the open state and form a seal around the spindle.