Features: The Valves have a self-sealing thread with rings. The automatic vent works with the help of source discs. If they come into contact with water, the source discs seal. When air, they open and let them escape. Make sure that this Valves is only suitable for heating water without additives. This radiator plug is make of Stainless steel and is very resistant to corrosion and the influence of external factors. Suitable for both hot and cold water. 3 operating modes: 1. The middle button is fully screwed in, automatic exhaust (it closes automatically when there is no air in the radiator); 2. The middle button is partially screwed, the vent is open; 3. Unscrew the middle button, the ventilation slots are closed. Widely used: automatic bleeding saves time and work, especially on many radiators in the house. Specifications: Materials: Stainless steel Styles: (1/2inch)/(3/4inch) Height: about 2.7cm/1.06inch Package Includes: 3pcs/set Automatic Bleed Valves note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.