The Hydrofarm Double Flange Kit works great with the Homebox growing tents, as well as other model indoor greenhouse enclosures. 

This dual duct flange kit allows you to run ducting from one side of your free-standing growroom to your HID light then out the other side wall of your greenhouse unit to exhaust the heat of your growlight bulb without releasing any fertilizer odors.

Pull the heat outdoors using an exhaust fan during warm weather. If you live in a 4-season climate, exhaust your bulb heat indoors to cut heating costs (it's odor-free!).

Duct flanges are made from thick formed sheet metal and painted on all sides. They attach to a matching fastener ring using screws. The kit comes with 2 flanges, 2 fastener rings and screws.

Indoor greenhouse requirements:

Clonebox - 4"
Homebox XS - 4"
Homebox L - 6"
Homebox XL - 6"
Homebox XXL - 6"