The No.75 Series Auto-Vents® Air eliminators for hot water heating and chilled water cooling systems. For continuous venting of hot water heating systems and chilled water cooling systems. Install on mains, pipe lines, unit heaters, chillers, convectors, radiant panels and coils. The No. 75 Series Auto-Vents are reliable, automatic air eliminating valves for concealed radiators, pipe lines, tanks and other devices where water or liquids are used for heating or cooling. They have proven to be the solution to problems that have confronted engineers and contractors in which air pockets or traps retard the free circulation of the liquids and reduce the efficiency of the system or appliance. The No.75 Series of Auto-Vent air eliminators are made of brass and equipped with a self-closing, float-operated valve. The valve is equipped with a Monel® metal spring and a Neoprene® valve seat which is unaffected by high temperatures, oil and anti-freeze. No air chamber is required. The vent is regularly fitted with a patented cap that may be used as a check in case of a leak caused by core sand or scale.