The Honeywell Two Port Zone Valve 22mm 721674/U is a compact, corded electric storage tank water heater designed for indoor use. With a sleek silver finish and a manufacturer warranty of 1 year, this boiler-compatible valve features a metal tank lining and a high energy efficiency rating of A. It is compatible with smart home systems, has a side water connection location, and operates on a voltage of 240V. Perfect for small heating systems, this valve is a reliable and efficient choice for your heating needs.