They look to be designed a quite a bit like a set of Lynx heads that I built and played maybe 10 or so years ago. This was after Golfsmith bought Lynx. The lower part of the heads were hollow and although they were fairly forgiving, they were not for the "Duffer." They were somewhere in between big time game improvement and player's blades, probably closer to game improvement than player's blades. I would guess these would likely fit there also.