It is used to automatically remove trapped air from a central heating installation, eliminating the need for this to be manually done. It has a shut off cap that can be used to stop auto venting if so required. This item has a 1/2" male thread to connect into a standard plumbing pipe fitting. - Size: 1/2" BSP; - Max. Working temperature: +100C; - Max. Working pressure: 1,0MPa (10 bar).