This is amazing. I've hammered them out many times trying to get a tight fit, and after that they're almost impossible to close They are certainly stiffer than their counterparts and although I have even attempted to test self-drilling these anchors I can start with a very small pilot hole and it will drill and screw fine in. As I am concerned about that big holes are formed I'd rather work on fixing those holes later to use an anchor more reliable than the other usual ones in a longitudinal shot.soon but that's exactly what I'll be buying again when that time is up.