2nd Bezel O-ring for Surefires?

I've read on here before that Surefires have space for a second o-ring on their flashlight bodies. I dug out my spare o-rings that I purchased from LightHound and went about doubling up the o-rings on my latest Surefire Lego Light. They easily fit on the tail end of the body and the extender but the head was a different story. It appears that there isn't enough room for a second o-ring of the same size as the original on the bezel end of the light body.

Can the o-rings not be doubled up on the bezel end of the C-Series bodies? I've heard that the M2 comes with double o-rings - Can someone check the bezel of their M2 to see if it has a second o-ring?

Thanks,
Matt

nope, the bezel end never has two o-rings.
Would not make much sense, because the bezel is not rotated under water anyway. Surefires bezel o-rings are rather big in dimension, i would absoluetly not worry about those.

Only one seal (o-ring/gasket) etc should be required - if the seal is sufficiently well designed, manufactured, assembled, and maintained by the user

Two seals are better for when having to rotate threaded components underwater is unavoidable.

Note there is a trade-off between ease of component rotation, and confidence in the ability of the seal(s) to perform as required.

I personally consider that the largest source of risk to the integrity of the seal(s) is the user's ability to care and maintain them - this is especially the case where threaded components are often rotated and/or the seals are often exposed.

In conclusion I don't consider there to be any need for there to be two o-ring seals on the bezel-end of a flashlight whose bezel is not expected or required to be rotated underwater.

Al

Got it. Thanks guys.

Size15's said:

... the largest source of risk to the integrity of the seal(s) is the user's ability to care and maintain them...

Click to expand...

This is 100% correct.

A diver's safety (sometimes his life) can depend on his light. It is essential to use a proper dedicated dive-light, AND to carry a backup light.

O-rings and seals should be minutely inspected every day, and preferably after every dive, to check that no cracks have developed, and no sand or other particles are present that might compromise the seal. After inspection, the O-rings should be carefully re-greased with silicone grease.

For non-divers this routine is obviously not as important; but divers who neglect to follow this procedure do so at their peril (and often someone else's peril too).

Further to Al's response, I have one of the mil-spec Infinity lights which has two o-rings in the tail, which is twisted to turn the light on, and it is noticeably harder to twist than the regular Infinity -- and probably not more waterproof unless you plan to dive with the light (which I doubt you'd do...).