I haven't seen the posts, but I assume you mean something like this. I recently ordered one of these for use on our machining centers. When I got it, I was quite disappointed. The center dot is very poor quality. It looks like the lens is cracked. The circles all look very good, but not the dot. It isn't going to work for what I wanted to do with it. I sent an email to the supplier did not good encouraging news. If you send me your email address, I'll forward it to you.
LittleMachineShop.com - Edge and Center Finder, Laser 3/8" Shank Concentric Circles