This package comes as 1 shrink-wrapped set of 4 silver oxide batteries with an output of 1.5 volt. These are replacement batteries for guide rod lasers that fit Glock 17, 19, 20, 21, 22, 23, 31 (with sn# prefix AA, AAA, B, BB, BBB, E, GGG), Sig Sauer laser systems (with sn# prefix CC, D, DD, Q), S&W Sigma 1240/1241 (with sn# prefix "AA") and 1911 full-size Government models (with sn# prefix CF). These batteries have an approximate 5-year shelf life.