Aprilaire #4522 Basement Kit for model 1750A / 1770A dehumidifiers.

Whole-home convertible to basement: The Aprilaire Model 1750A / 1770A Dehumidifier can automatically switch between whole-home and localized dehumidification, allowing you installation flexibility in basement and crawl space applications.
Automatic switching allows the system to provide dehumidification to the whole-home when the air-conditioning is on and then converts to a specific location (i.e., basement) when your customers turn off their air-conditioning. Available for both finished basements and unfinished basements.

Kit contains:

• (2) 6508 8" round normally closed damper
• (2) 6608 8" round normally open damper
• (1) 8029 plug-in transformer

Please refer to this document for installation information.