I have a couple of them, one in a AXA block and another set up as a threading swing tool (also is a AXA block), they are okay, they work good, but they have some limitations, they are just about useless with any thread number above 13 TPI, the insert is just too wide. They will do 1/2"13 great, but 1/2"-20 is too fine. I have the insert number, somewhere on a piece of paper, you can buy them directly from China for $2.
I thread a lot of stuff at 6-10 TPI, for that they work great, but if you looking for a more universal tool, this ain't it.