Now you can swap out a variety of background into your studio space to suit your broadcast or sponsors. Also great for multi-use performances spaces, houses of worship and corporate event centers where a simple change in the backdrop can tranform your space to suit your application or presentation. Fan-shaped switching devices are designed for use on”WALK-ALONG” tracks (Models 142, 142-R, 422 and 422-R).Note: Track switchers can not be flush mounted to the ceiling. If used with a flush mounted track system, an opening in the ceiling surface will have to be made to allow for the top of the switching device.Left and right hand switchers, for model 142, 422 and 502 track systems, offer the option of motorized operation (MTWS).