Wrote an extensive review and it was taken down. Do not trust this company. Sight itself is defective in design. You've been warned.
Easy to rail mount on my Ruger MK IV. It takes a bit of practice to use the sights but fairly accurate at 20 yards.
The first sight had a problem the company was quick to resolve issue , and I am quite satisfied with the product
Mk2 - Tritium Night Sight Rail Mounted