Tailcaps: G2 vs G2Z - Is there a difference?

Does anyone know if there is a difference in the G2 and G2Z tailcaps? Recently, I have seen photos of a G2Z tailcap, and it looks like the grooves on the outside are longer than those on the G2 tailcap (I'm referring to the older G2 version). Also, I notice that the G2Z cap has a 'witness mark' notch on it, which my G2s do not have.

Are there other differences? Is this just a newer version?

To clarify, I'm not talking about the very old G2 tailcap, the one where the switch 'guts' will drop out; I have one of those, and it is definitely shorter than the later ones that were truly lockout-capable.

The newer G2 tailcaps have the longer exterior grooves as you've observed.

Although I have not owned a G2Z, I would expect the tailcaps to be identical across the two models.

With regards to interior changes between the two generations of tailcaps, the only difference is that the second generation tailcap has a very slight shoulder per my photo below:



The only real impact of this difference is that the newer style tailcap is incompatible with a second body o-ring if you were to add a second o-ring groove to the body tail (as the aluminum SF bodies have).

Thanks, Kestrel for the detailed and informative reply.

I, too, had always assumed that the G2 and G2Z tailcaps were the same. When I recently noticed the difference, it was on a G2Z, so I thought maybe they were different, and I had just never noticed before. (I have never had a G2Z, either.)

The info about the ridge is particularly interesting, because I am currently using a 'borrowed' G2 tailcap (an older one) on a C2 I am putting together. I find I kinda like the look, but if I decide to get a new G2 tailcap, I now know I will not be able to use a second O-ring. (Personally, I've always questioned the benefit of a second O-ring on the tail, when the bezel only has one, but that's another discussion.)

Thanks again for the informative response.

My apologies if this takes the thread off topic but in answer to 'justlooking' the benefit of two O rings on the tailcaps on Surefires is because of the twisting motion that tailcaps are regularly subjected to. Even on Surefire models with clickies the tailcap is usually regularly twisted to 'lockout' to prevent the light coming on unintentionally. With more frequent use the risk of a single O ring becoming degraded and worn obviously increases. The older incandescent Surefire models would of course also of had their bezels removed occasionally for bulb replacement. However, compared to the times that you twist a tailcap Surefire must of felt comfortable with the reduced risk of O ring damage to the bezel end and kept with a single O ring? Nowadays of course many of the newer two cell models Surefire has brought to the market are usually sealed at the bezel so water ingress isn't usually an issue. I suspect that one O ring regularly inspected and lubed is more than adequate for the majority of tasks that users subject their Surefire flashlightslights to. However, Surefire has in the past supplied limited numbers of its smaller flashlights, such as the 6P, to the military who had a 'dive' requirement. No doubt two O rings would have helped or been a necessary part of getting a light passed as meeting those requirements?

Happy to be of assistance. Good point dougie, yes I have utilized second o-rings on G2's - not to get increased water resistance but to increase the twisting resistance as noted above. I find that the Nitrolon surfaces have extra lubricity that can enable the tailcap to twist too easily, potentially turning on by itself, etc.

And of course, after having great difficulty with the newer nitrolon tailcaps, I found the interior shoulder to be an issue with regards to secondary o-ring clearance.

Thanks for the info, Dougie. I've converted my most-used lights to McClickie, so I tend to forget how often a stock Surefire could have the tailcap twisted. I also try to check the O-rings whenever I charge the batteries, to make sure they aren't dry on the surface that contacts the tailcap. I bought a used light recently that was so dry, it actually squeaked when I turned the tailcap.

Thanks again, to both of you, for the good info. Now, maybe I should start looking for an older G2 tailcap, to avoid the problem Kestrel identified..........