I made the mistake of buying the power custom stoning fixture. So far it's been a bad investment. I'm $400 in and so far I've only managed to ruin trigger groups. I didn't know I needed THEIR stones. I also bought the wrong AR15 adapter or so I thought. Turns out I may have had the right one, but had already bought the other one. Neither fit like the one in the video. Bottom line is, I'd like to learn to use this tool and I've run out of triggers and hammers to ruin. If anybody has any they'd sell me for cheap enough, I'll take as many as I can afford. At this point I'm determined to gain the knowledge from this purchase. You can text me 83O 26l 8963.