Ratchet Mount Antenna Base The robust design on the Ratchet Mount Antenna Base fits deck or bulkhead mounting with a quality that far exceeds those lesser expensive plastic units. To utilize on our Fishmaster T-Top, use with Folding Antenna Mounting Plate for an exact fit with mounting hardware included. It can then be clamped to our ttop tower tubing and adjusted with the double pivot system. The Fishmaster Ratchet Mount Antenna Base has universal 1"-14" male threads that are CNC cut for precise thread engagement. Its unique two system ratchet design utilizes a lever for lowering or raising an antenna. The secondary ratchet allows for adjustment to the opposite side either left or right. Shims are not required because of this two (2) axis adjustment. Works on almost any antenna for GPS, FM, AM, and VHF that accept the standard 1"-14" marine industry threads. Complete the assembled use four (4) flat head stainless steel 1/4" threaded screws that are 1" in length as a minimum.