The tailcaps on the G3, G3L, G2Z & G2ZL are identical. The G2 tailcaps can also be used on the above-listed lights, and vice-versa; However, the G2 tailcaps differ by not having the side grooves running the length of the tailcap, and they do not have the "USA WWW.SUREFIRE.COM" on the top of the tailcap.