I used these to build the Hypercube Evolution, they do the job but you have to be careful when reassembling as you use M6 set screws and if you push in too far the screw can dislodge the two tabs and mess up the alignment. Also, the thread was cut in the opposite direction of the screw, sometimes the set screw can't get into the hole, so you need to cut it completely from the opposite direction to allow the screw to free the thread and then insert it as intended.