The C.E. Smith Company Transom Mount Aluminum Rod Holder is designed to mount your rod holders to the transom or seating areas. The 1-5/8-inch inside diameter with flared opening allows for easy insertion, while the taper liner and rod security hole provide increased protection. The holder mounts vertically or at an outward angle. C.E. Smith Company Transom Mount Aluminum Rod Holder - Marine Accessories at Academy Sports