A mounting curb is recommended for installing your roof exhauster. This 12" high mounting curb is welded, prefabricated, heavy-gauge galvanized steel with a 1.5" wood nailer and includes insulation, damper shelf and mitered 3" cant. The outside dimension of the square curb is 16 1/2".
The 711216 is for use with all SDB and STXD sizes 6-10, and STXB Size 8-10 model roof exhausters including single and triple phase models.