Truglo TFX or TFO.
TRUGLO(R) | Firearms | Handgun I just put the TFOs on my Shield and am very happy with them. Both the TFX and TFO are a combination Tritium/fiber optic sight, highly visible day or night. I have the Trijicon tritium night sights on my FS M&P9, and if you have trouble seeing regular white dot sights in the daytime, you will likely fare worse with the Trijicons..