Constructed from galvanized steel with bolted frame, USF-200 has backward inclined centrifugal wheel and suits Class I airflow and pressure applications. Capacities range from 50–13,700 cfm and up to 5.0 in. wg. Used when coating on housing and in airstream is required, USF-300 offers capacities up to 54,000 cfm and 5.0 in. wg. With painted steel construction and backward inclined or airfoil wheel, USF-400 is capable of Class II applications with capacities up to 69,000 cfm and 8.5 in. wg.