Read this and understand what you are getting - POF USA Dictator Adjustable Gas Block

This gas block is as close as you can get to the adjustable gas blocks on production rifles. No set screw for gas adjustment, just dial your click an you're set. But, as mentioned in other reviews, the midlength gas tube that come with the gas block is too short for DPMS pattern AR10s. I assembled my blaster from Aero Precision parts and a Criterion barrel, and the gas tube did not seat in the gas key at appropriate depth, causing the gun to short stroke even with the gas block opened all the way. I ordered and custom cut a straight gas tube, not only to length, because the POF part results in a non-standard tube length, but I also had to make cuts for the cross pin that mates the block to the tube, which is again non-standard. I enjoy tinkering, and even so, I was a bit frustrated with the amount of work I had to do to get the gun to run. Conclusion: Super nice part that, at the time of this writing, was not offered similarly by any other parts manufacturer, that takes quite a bit of work to get to function.