Peerless-AV ACC625 Dedicated Wall Adaptor BoxExpandable depth control (up to 5. 5) provides extra depth adjustment to help short throw projectors get the throw distance needed to achieve a great picture when a Whiteboard is mounted over a chalkboard. With these two Dedicated Wall Adaptor Box models that are compatible with short throw projector arm models SMART Arm 6i, SMART UX6 and Hitachi A1WALLARM2, there is a solution ready to help create the perfect picture in virtually any setting.