A must have tool - Midwest Industries AR-15 Lower Receiver Block

I purchased this lower receiver block during my first AR build, and have continued using it for other builds and general maintenance. I have used it multiple times for setting roll pins in the gas block/tube, and while installing the bolt catch in the lower. It also comes in handy for disassembling the bolt extractor/ejector for cleaning and when properly checking headspace. I'm sure there are many other uses I'll find for it along the way. It's designed and built well. A must have tool for assembling AR's well. Only gripe I have is it fits loose in my lower's magazine well, causing it to slide off the magazine catch without even depressing it. Had to be extra cautious with hammering in roll pin for bolt catch.