Right sight, Wrong size
The sight itself is perfect, however I bought it for my Echo1 Genesis M4 and it was to small to fit over the outer barrel and I had to use a drill press to bore it out some more. Now it works fine and stays on tight. I used a micrometer to find the diameter of my outer barrel and it was 0.755" so just know that those few thousandths of an inch will need to be shaved off.