It is the Bakflip MX4. The RamBar squeezes the rails in about 1/8th in on each side. So that requires a little filing of the bracket to make the bolt hole large enough to line up in the front. It is on the inside, so no one will ever see it.
It also does not open all the way as the RamBar is angled towards the inside of the bed. I could live with that as I do not use the bed a ton.