That looks like it should be the right buddy box for your Focus 4, Skeeter. Hitec is in the middle of remodelling their website, however, and unfortunately a big part of that remodelling includes removing useful information from the site. You should be able to hook up your Focus 4 to a Hitec buddy box or to another Hitec radio easily enough, if you find a good deal on another Hitec radio you can use it as a buddy box instead of the dummy Laser 4 shell. If you like the other radio more than your focus, just use the focus as the buddy box.

A quick phonecall to Hitec will confirm this. They used to have information about "retired" radios like your Focus 4 on the website, but it's no longer there.

Good luck and good shopping!