My g/y meps are 2 1/2 yrs. Old and the yellow is pretty dim. Cause that i now go g/g for longevity of the tritium
Might be worth inquiring with Meprolight/Kimber about that. The yellows should have the same longevity as the greens as Meprolight warrants both for 12 years. The orange ones are said to be short lived and carry only a 5 year warranty. Bill