This is a great receiver, once you get it on. I installed it on my A&K M16A3 with stock externals and internals. It is a real tight fit on the A&K M16 Plastic Lower Receiver and on the gearbox. If you just put it on, it didn't close all the way and also was shorter than the lower receiver. The tabs have to be pushed very hard to get in the lower receiver. The holes in the tabs were also smaller than the body pins for the gun, so I had to file and drill the holes bigger. Put all of that work aside it was very easy to do and works the way it should, after modification.
-Nice black finish
-Imitation Gas Tube
-Metal Rails, Charging Handle, Dust Cover, Barrel Connecter
-Does what it needs to do
-Had to modify it
-Tight to get around the gearbox
-No imitation bolt (but it doesn't matter anyway)
-Somewhat cheap material.