The BB-111381 vent hood is a wall-mounted, wide-mouth exhaust hood designed to terminate 4-inch duct runs (for dryer vents, attic fans, or general exhaust applications). It features a molded polypropylene (plastic) hood body with an aluminum trim / tailpipe. A built-in back-draft flapper prevents unwanted air or pests from entering when the system is off, and a snap-in pest grid (bird guard) protects against insects, rodents, and debris. The tailpipe is factory-installed and riveted, facilitating straightforward installation. The wide-mouth design helps reduce airflow restriction at the hood opening.

It’s commonly used in residential ventilation systems to provide a low-cost, durable termination point for duct exhaust, while offering protection from backflow air and pest entry.