Review (3/5): While they do add support/lift, they do not fit 25% of my post earrings and are awkward to use
I tried these with 20 of my post earrings and they fit 15 pair. For the ones that didn't work, I couldn't get the post through the backing hole - it was just too small and the common factor for those is that those posts have "ridges" (which I have always thought were intended to provide a tighter, more secure fit into the backing).
While these backings do provide some lift, I found them somewhat awkward to use/put on, both because they are considerably larger than typical backing and the need to ensure the heart is facing up.
3 stars, because they do work with some earrings and they do provide lift. 2 stars off because they do not fit all of my post style earrings and they are awkward to put on.