Bought it for a Remington 870. It was hard to put it on properly and aligned to the center. After shooting it moved and shifted off center. Not worth the money. It is bright, though.
My vision has faded quite a bit the last few years and I was having trouble seeing the bead on my Winchester 1300 defender. This sight went on easy and, while it's still not crystal clear for me, it is a big improvement. Also, the sight stays solidly on the gun.