looks like some tricky machining underneath that button head bolt,

seems like a better system than the tapped out hole in the stem, have seen some stems with what looks to be excessive bending/warpage along the front of the binder aluminum section, as that is where it bends when spreading it out for new bars,

i almost bought the stem on the right till i noticed an oblong shape in the handlebar hole, you can see that it was not making contact with the bars from the lack of grooves,