1/2″ Hudson Auto-Fill Wall Mount Kit. The unique patented design of the Hudson Valve uses fluid pressure, as opposed to a lever arm and ball, as the force to close the valve. This compact, self-contained design greatly enhances the valve’s reliability. Fluid level forces the float to rise and close the diaphragm chamber, which expands to stop incoming flow. This kit includes a wall mount in addition to the Auto Fill Valve.