Ventilation - Air Filter Box 6in
FB6 In-Line Filter Box w/ MERV12 Filter, 6" Duct
http://www.supplyhouse.com/Fantech-FB6-FB6-In-Line-Filter-Box-w-MERV12-Filter-6-Duct $83.55
Installation: http://www.fantech.net/Documentation/Fans%20and%20Accessories/402690%20FB6%20Spec%20Sheet%20%20EN.pdf