Hi there, I see another piston thread. It's interesting this make gets dropped from the suggestions:-https://imdpistons.com/collections/a10
Made in UK, perfect rings. You might search for the threads that include "IMD", that will tell you all the benefits I (and others) found. They are flat top, but my compression came up by skimming anyway. The owner, Adrian, has posted himself in this forum. One of the benefits he offered was a sleeve set, that had flange at the top - so they can't drop or twist...