Product: Fantech FR 110 Inline Centrifugal Duct Fan, Molded Housing, 4"
Brand: Fantech
9 sizes with airflow capacities between 150 and 650 CFM
Vibration welded seam ensures leak proof housing
100% speed-controllable
Air stream temperatures up to 140 °F
They are also widely used as booster fans to move air from one room or area to another

Search query: inline duct booster
Relevance: Exact