Light duty but works - AIM Sports Inc AR Armorers Kit

I used this kit for a lower build. The lower vise block is slightly loose in the magazine well, but works. The upper vise blocks fit my PSA upper and lower but I did not use them to change a barrel so I can't adequately evaluate them. I see no reason why the upper vise block wouldn't work. The armorer's wrench is magnetic, so it's ferrous, but whether cast iron or semi-steel I can't say. I used the castle nut end with three prongs to tighten the nut for my buffer tube. The prongs fit my castle nut - I believe the components supplied by PSA were a Magpul lower build set. There is no square socket hole near the castle nut end to use for a torque wrench, so I tightened mine by feel. The square hole close to the barrel nut end does fit the 1/2" drive of my torque wrench correctly. The square notch fit the flats on my flash hider. With regard to the barrel nut end, I have read somewhere on line that as long as you get all three prongs into notches in the barrel nut, the wrench will work. If you try to only use the two opposing prongs on your barrel nut you're likely to break one of the prongs off. My upper came preassembled, so I didn't need to use this end of the wrench. The front sight adjusting tool is light weight sheet metal and the prongs on the ends bend easily - mine arrived with one of the prongs bent in so that it wouldn't fit over the front sight until I bent it outwards to straighten the prong. I tried it on a metal sight and technically it worked, but there's a high risk of breaking off the prongs of the front sight tool. The metal on the front sight tool struck me as being made of relatively soft steel, but I have no known good one for comparison. I'd say this kit is good for the person going to build one or two AR's, but if you're constantly needing to change barrels, you'll be happier with a better armorer's wrench.