I was selling them for Steve way back when. Again, the concept was good and when they did work, they did as advertised. But... they were very easily damaged during installation in many guns, were not very dependable and had a high failure rate and got a lot of complaints and I had to send out quite a few (way to many) replacements. I was sure glad when it ended because it was a pain to deal with.
Also, in my opinion, they are/were way over priced at $20.00 but then I wasn't the one that set the price. In fact, when we split, I sold off most of what I had left for $8.00 I think it was and still made a decent profit. They were very inexpensive to make. I did hold a few of each back and didn't sell to play with myself.
So that said, those of you that get them, don't expect too much but hopefully some of you will get good results.