This JVC HZ-FM15 Focus Manual Servo Unit is a great choice. Note that it doesn't come with a cable.

Using this JVC HZ - FM15 Focus Manual Servo Unit is easy. Just connect it to your compatible device and start adjusting the focus. Remember, it doesn't have a cable, so you'll need to use your own. When handling it, be gentle to avoid any damage. For maintenance, keep it in a dry and clean place. If it gets dirty, you can use a soft, dry cloth to wipe it. Don't expose it to extreme temperatures or moisture, as this can affect its performance.