The 20-40-60 control is for installation in a bathroom, a laundry room or a workshop. This auxiliary wall control can be installed with any main control of the AI series.
Broan-NuTone® Control, Plastic, White, Wall Mount, 1.2 in Width, 2.6 in Height, Additional Information: 20-40-60 min Set Time
Catalog
Video Link- Cont - max speed exchange ventilation for 20 min, 40 min or 60 min