The installer I went to used these brackets they are 2 identical parts per corner. So they are tilt upgradeable. I won't go back to them because of the mistakes they made with the Victron equipment. I've searched several weeks on Google and Solar websites and asked another Solar installer in town nobody has seen them before. They are probably generic for other uses. I want to add 2 more 200 Watt panels to the RV roof and stay consistent with the mounting brackets. Any idea where to buy these? Thanks