Hmmmmm maybe a half dozen. They last long enough I forget when I put the last one in. Is it a trijicon no but it cost 1/10th the price and gives 75% of the performance.

JYD#176
"dein Gott schickte mich zu zerstören"
"Sic semper evello mortem Tyrannis"
"Sometimes the chance of a zombie outbreak is the only reason I need to make many of my life's Decisions." General Delivery