Hi wmgeorge,
In the short time that I have had it I like it. i was able to us the Mach3 probing wizard and probe a piece of angle iron with the angle pointing up. The probe works well and is durable. I drove it straight down into the vise and all i did was bend the tip. The probe was not at fault as I was testing some specialty stuff and it didn't work correctly.
The probe comes with a female stereo plug so all you have to do is wire that in.
The ball is approximately .125 or there abouts but I don't remember exactly. If I remember the tips are not made to an exact size and for most of the probing wizards you can set the tip diameter.
I will be making a new probe tip since I bent mine.
All in all I like it and hope to get some of Himmykabbibles probing wizards and tool length macros put into play.
Of course I need to quit my day job to get it all done in a reasonable amount of time.
Mike