Good buy, but one warning. - HiViz Fiber Optic Light-Pipe Walther P99/S&W 99 Pistol Sight

This sight is for my Walther PPQ M1. I would have given this sight a 5, but there is one problem. In order for the sight to be accurate, I had to insert a shim on the top of my slide. This is the second HiViz sight that I've ordered for my PPQ. Both have needed a shim to be accurate. The sight itself is great. I especially like the cover on the fiber to keep the fiber highly visible. My M&P came with a fiber optic front sight, and I have to replace the fiber a couple of times a year to keep it visible.