#C - 1/8" Angle Radiator Steam Vent, Maid-O-Mist JacobusMaid O Mist Jacobus Model # C Venting capacity equal to 15 ordinary air valves. Use on radiators farthest from boiler and in coldest rooms (for example, on third floor radiators and above). 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 thermostatic element