Nice addition
I purchased the medium and put them under the insole in a pair of 8.5 Metcon sports.  I trimmed it so it would fit flush to the bottom of the heel bed.  When you put them on you notice the heel is sitting a little higher but it hasn't caused any problems and I didn't notice any difference while working out.  I haven't noticed any difference with cleans, front or back squats but I didn't have any issues with hitting depth on those lifts.  I did notice it was easier to get lower while doing overhead squats and snatches.
Rating: 5 stars