I have a round 4 caps and I did try it on a Poker 2 and while the feel is great, I find that the taller round 4 caps didn't look as nice on the Poker - they made it very cramped and dense. I bought a Vortex ONI TKL keyboard and the round 4 looked much better there. I'll post photo later. Point is, I think the SA profile fits a larger keyboard aesthetically.