Expel all the hot air, cooking smoke and grease particles from your kitchen through the Bosch Wall Mounted Pyramid Chimney hood duct extension. It is suitable for large kitchens and tall ceilings between 9” to 11.5”. This duct extension is made of durable materials that can withstand heat and are resistant to smoke, oil, and dust particles. | Bosch Wall Mounted Pyramid Chimney Hood Duct Extension (HCPEXT4UC)