Is there a reason why you want to get such a small capacity one again? I don’t want to interfere if mal or someone else who is a much better expert than me recommended it, but if you are just going by the official Fairphone specs (which claim you could use just “up to 64 GB” ones), let me just say plenty of Fairphone users have used much larger capacity SD cards in FP2s. I have used a 400 GB one without issues (not much Sailfish OS experience though).