This is a dedicated post with a base attachment. The lid on the inside of the shoot maintains an airtight seal and prevents sound and blowing when opening and closing the lid. Specifications: Receiver: Width: 15.7 inches (400 mm) Height: 3.8 inches (91 mm) Outlet Opening Dimensions: Width: 13.0 inches (330 mm) Height: 2.7 inches (69 mm) Wall thickness adjustment range: 3.7 - 5.5 inches (9 inches (9 inches (9 inches (140 mm). Country of Origin: Japan. Material: Receiver: SUS430 mm). Lid: ABS resin.