Flow Right Filter Cabinets are RTA HVAC filter boxes with a patented knock-down design for easy storage and quick assembly. Made from durable galvanized steel, these adjustable height cabinets improve airflow efficiency by up to 20% compared to traditional 4-inch media air cleaners, reduce equipment strain, and can function as a booster box without the filter door. Adjustable height adapts from 4" to 18". Ready-To-Assemble (RTA) design allows fast setup. Ships in a flat carton for easy storage.