UFC Complete Polycarbonate Hop Up Chamber for AK Series Airsoft AEG Rifles

"It works. I just finished building an AK-47 from boneyard parts, just needed to buy the barrel and hop up and a few screws and the thing is functional, shooting around 367-370(in my field's limit to -400fps for anything [except for actual full day events], including sniper rifles). Simple to put together:
1. Align hop bucking (included) on barrel
2. Place barrel in hop up and c clip and screw to trunion
3. Insert nub on top of bucking (takes a bit to align right)
4. Insert adjustment arm and use plastic pin to lock in place
5. Insert slide on hop up and screw in on right side.
It is all plastic except for the 3 screws and it does not have the extension arm to move the nub slide, so just use a toothpick to move it. I can say it does work, not the best in the world, but a good cheap and quick replacement.