Good replacement sight - XS Sight Systems Dot Tritium Sight

Sight is the perfect size dot for my J-Frame 640 revolver. The dot fills the frame "U" notch making for quick and precise sight acquisition. I think that the "big dot" might have been too much. Installation is simple but, you will need a #54 (1.040 mm) drill bit to make the hole for the retaining roll pin. These tiny bits are fairly easy to break so, you might want to get some extra ones. I used a Dremel to dril the hole as it holds the tiny bit and is far easier to handle than a standard drill motor. Take your time and follow the instructions.