This adapter must be used QC 1500 if you are going to to mount it vertically on a wall. For use with the CL-1500 and ES-1500 Quiet Cool Whole House Fans
The adapter ensures the dampers on the close all the way.
Feel Free To Call Us with any Questions 1.888-229-5757
DBA Whole House Fans
29021 Ave Sherman STE 103
Valencia, CA 91355
Toll Free: 1.888.229.5757