The Length Extension Kit is designed for those who need longer enclosures. Two 4’x2’x2′ enclosures can be connected to create an 8’x2’x4′ enclosure. Connect a 4’x2’x4′ enclosure and a 2’x2’x4′ enclosure to create a 6’x2’x4′ enclosure. Note: Not compatible with Meridian Enclosures