I am the guy that use to sell them on ebay several years ago. I primarily Drilled and fit 8 balls with a pump arm for the Phantom pump. I still have all the specs and may start making these again if people are interested.
I have one on my gun and I like it it has a pressed in threaded insert for the rod to thread into I just bought the gun but I've known the person who's had for like around ten years and it's never broke if I can figure out how to post pics I'll throw it up