This mount comes with the adapter plate (AD-1) that you can thread right into your control head. Your control head has a 5mm threaded hole that the AD-1 can be attached direclty to. Nothing else to buy..Good Job Yaesu.
Here is a youtube video on how it all hooks up.
Strong yet flexible aluminum mount recommended for service vehicles and trucks
Compatible with GPS, cameras, and other devices having a 4-Hole AMPS pattern
28-inch gooseneck and swivel ball provide ideal positioning of device
2 year limited warranty
This mounting pedestal is ideal for mobile radio holders, housings, and other devices used by public safety, construction, and utility applications. The car seat rail mount is made of strong yet flexible aluminum, and is ideal for service vehicles, trucks, or those who need easy access to their devices but prefer mounting them somewhere other than the windshield or dashboard. Use a socket wrench to install the mount to the car’s seat rail. Loosen the passenger seat track bolt, insert the included seat track bolt bracket (2 different brackets are included for various seat rail configurations), and then retighten the bolt. Bend the 28” gooseneck and rotate the swivel ball adapter head for 360-degree rotation for exact positioning of the device.