These blocks are made in China BUT for Chinese junk these are very good. Why? Well they are accurate on all measurements coming in at exactly 1.000000 x 2.000000 x 3.000000 verified on via my probing machine. They are perfectly square as well. The bolts are properly threaded for 3/8 x 16 bolts and there is enough meat on the untapped holes to tap them on a mill if needed. I do recommend running a thread chaser not a tap through the tapped holes to clean out the coating as some of them may be dirty. So to the guy who gave them one star you know the creep in the street guy well he either a didn’t clean the threads or b used the wrong thread pitch bolts. Either way he is a whiner as he is crying about very cheap Chinese blocks. If he wanted perfection he shouldn’t have gone out and bought an expensive precision set but he didn’t cause he’s cheap and just wants to complain because he’s a troll.