A quick look at my flatwater OEM fin from Skatinger that is 9 inches high (or deep) vs. my low-profile river fin that is longer with a four inch vertical rise. I have a bit less stability with the river fin, but I don't drag bottom in most places in the river and in shallow lakes now. It's my go-to fin unless I know I'm going into deep water only. They're about $20 on Amazon and I had to spend another $10 for a box of spare screws and nuts because the damn things go missing over the season.