Guys the net is full of collet blocks,just starting out and I need this for one of my future projects.Looking at the 5C cause watching Youtubes saying that the 5C has more holding power for little longer pieces.But as I search either on ebay or All Indust. they all look the same but which ones is more accurate than the other?Say I'm using the square holder as you rotate it to machine a part if its not spot on well neither will your part.Na not making nothing for Nasa but for 50.00 or so I would like it to be the best it can be.What vendor would you purchase your blocks from that are good?