You get what you pay for! - JE Machine Tech AR-15 Aluminum Carry Handle

This part seemed to be quality until I got to adjusting the the rear sight. Total junk! this thing moves around like crazy and I'm sure will never hold a zero. Also, there is no mark on the aperture to center the sight or reference. When flipping between the two apertures, the left/right adjustment knob would back off one click each time. It appears to be threaded for a set screw, but one was not provided. It is my own fault for going cheap, however, I have purchased other inexpensive carry handles in the past which were very good.