Light traps are an essential feature of any light deprivation greenhouse operation. They are placed over any ventilation opening in the greenhouse structure in order to block light without sacrificing the efficiency of the fans or vent they cover. Light traps should match the size of the fan with which they are used  When the structure is blacked out, air exchange is often necessary but difficult to achieve without light pollution. These light traps make that possible. Other sizes available.  Light traps consist of plastic fins, specially designed for optimal airflow without letting light through, with a sheet metal casing. This allows for open ventilation and efficient air exchange while in blackout mode. It can be used as a passive air intake alone, or to cover intake louvers and exhaust fans, but it allows air to pass without letting light into the structure. Can be used for both exhaust and/or intake.  Unit comes assembled ready to use Large inventory of all size light traps are in stock. We are located at zip code 93536. You are welcome to arrange local Pickup.