Speaking of OX Lockers... That's what I will be installing in the front of my F350 eventually. They are a small US Company based out of Florida. They also back up their products. Plus they also come with a sweet HD diff cover
They can also be actuated pneumatically, electrically, or with a cable. They are also the only selectable locker that I know of that has a threaded adapter that you can use to manually engage the locker in the event the cable seizes or snaps. Though I will have onboard air, I have chosen to go mechanical with a cable when I do it. I prefer to keep everything as simple and straight forward as possible.