Great aftermarket sp101 front sight - XS Sight Systems Standard Dot Tritium

I put this sight on my 2 1/2" Sp101 revolver. It did take some work to install, drilling was required to secure the sight. But the sight fit into the slot without issues and it wasn't very difficult if you have any experience working with tools. A small amount of permanent lock was provided with the purchase too, if you're not planning on changing it out. I went with the small do over the big dot and am happy for the choice, the small fits the rear grooves wonderfully and I can align the tops with ease for my sight picture. The big dot requires a half circle picture (lining the front dot half way into the rear groove). The white is eye catching and the tritium is a nice comforting glow. No complaints and I'd call it an easy and very worthwhile upgrade to your Ruger Sp101.