This item can be used as a part of a long ductwork run for a variety of purposes including whole-house ventilation, passive stack vent, positive input ventilation, air conditioning, HVAC, and Heat Recovery systems- Perfectly suited for ducting your bathroom or kitchen extractor fan, hydroponics, in-line extract fans, tumble dryer, or a cooker hood- HIPS material- Suitable for use with the ventilation system- Grille 4-Inch Terracotta- Easy to install and durable