#D - 1/8" Angle Radiator Steam Vent, Maid-O-Mist JacobusMaid O Mist Jacobus Model # D Venting capacity equal to 27 ordinary air valves. Use when large amount of air must be vented such as on radiators with particularly long branches and on very large radiators. Features: Self adjusting thermostatic control Float to prevent water escape Reduces radiator noise Cut fuel consumption Assures even heat distribution Lower operating costs Improved nickel plated brass body, valve seat, solid float and bi metal