The LWF122I is needed to connect an LF92I or LF122I into a wall or soffit. Fortress lineset cover series was specifically developed to bridge the gap between the lightweight and the more costly lineset cover products available on the market. Made in the USA, Fortress has a number of of innovations to suit the USA conditions - such as 8' lengths of duct and a 12 month guarantee. Available in 2 sizes and 4 different colors Fortress offers the strength and longevity at a moderate price point.