Removed from a Glock 17 properly using proper tools, by a Certified armorer. Sights are like new. H3(Tritium) is the chemical which glows inside the ampules that are embedded in the sights. Tritium has a 12 year half-life. Meaning they are warranteed to stay bright for 12 years. These are 4 years old, they have 8 years left of service.