The Resideo VR8215S1214T is a single-stage direct ignition gas valve for the regulation of gas flow in HVAC systems with high reliability. This is a 1/2" valve that works at 24V and it has a feature of rapid opening for it to meet the heating demands as soon as possible. For an efficient and reliable HVAC system, the Resideo Single Stage Direct Ignition Gas Valve is a great choice... https://www.partshnc.com/vr8215s1214t-resideo-12-24v-dualdirectign-gasvlv