The HART & COOLEY 5RYF44 019511 5X4X4 B-VENT WYE Double Wall Furnace Vent Exhaust is a single unit manufactured in the United States by Hart and Cooley. This fitting and adapter is designed for use in double wall furnaces, providing a reliable solution for venting and exhaust purposes. With its durable construction and quality brand reputation, this product is an essential component for industrial and commercial heating and cooling systems.