I bought 20 or so BoomerShooter lowers way back when we got those done. I bought several Of these tools to make building all those lowers easier and it is. I have a trigger guard install block and its super easy/fast and with the roll pin holding punch it's so much easier. Roll pin punches, a Brownells flat pinch for installing the bolt catch pin is worth the $. I also really like the front take down pin detect install tool. No more pins and springs flying across the room. If you build enough of anything having time saving tools that make the finished product better are worth the $ imho. If anybody local wants to try any before they buy let me know if be happy to show you how they work for a small fee of a sixer or two.