(12x24") Light-tight, heavy-duty metal louvers that allow fresh air to pass through freely. Most efficient when used with a Darkroom Fan. But one or more may be used to ventilate the darkroom. 12x12" for a room up to 12x14', or 12x24" for a room 12x20'.
Reviewed by 1 customers
I am setting up a darkroom, and ventilation is critical. This was a perfect fit with being light tight.