Active Ventilation Box is 21 in. Wide x 21 in. Long x 6 in. High Aluminum Roof Curb RC-18-H6 - The Home Depot
Universal Canted Roof Curb For Ventilation Fan 16 5 X 16 5 X 12 56807 | AC Pro Store | HVAC Equipment, Parts & Supplies for Contractors
Installing the Roof Top Package Unit
Hinged Exhaust Fan Base/ Fan Curb Adapter CaptiveAire DU85 23"x23"x20"H | eBay
Roof Curb Dimensions 12" Square x 12" High, Model RC-9-H12
Fan Curb Adapters | Galvanized Fan Curb Adapters | Curbco
Amazon.com: Restaurant Canopy Hood Grease Rated Exhaust Fan- High Speed Direct Drive Centrifugal Upblast Exhaust Fan with speed control- 24 3/4" Base, 0.75 HP 115 Volt Single Phase Motor, 1500-2200 CFM (DU85HFA) :
Roof Curbs & Mounting Accessories | Greenheck
Roof Mounting Curb for Soler & Palau brand Model STXD Exhaust Fans
Exhaust blower package for 4 foot fume hood | KA Centrifugal Upblast R
Paint Booth Roof Exhaust Fan Systems - Carl J Bush Company
Flat Curb for Roof Mounted 48B Exhaust Fan
Exhaust Fan Curb Adapter
Installing the Exhaust Fan
Insulated Roof Curb 21" x 21" OD x 6" High - Aluminum Roof Curbs
Roof Curb Dimensions 15" Square x 12" High | Model RC-12-H12