Works on both horizontal and verical vents that are 1 inch or less in depth. The control is attached to a swivel to adjust your control head for the view you want tightening ring to tighen the hook onto the louvre for a secure fit Can be attached directly to the control head without an adapter Vent mount with hook design to securely hold a Yaesu FTM series control head or a FT-891. The faceplate has a swivel so you can adjust the control head to get the view you prefer. The hooks arm length is controlled by a tightening ring. This allows for a snug fit on the vent louvre.