BS, BS, and more BS. All anyone has to do is go to any site that reviews lights, like Amazon, Road Bike Review, etc and you will quickly learn that no one has had a problem or has complain about water, and or moisture getting in their lights or in their light switches and then the light failing.

I suppose you're right. While light heads haven't been an issue (thought I've had condensation inside my MS900), batteries are another issue. There have been hundreds of posts on these forums about the original Magic Shine battery not being water-resistant. There have also been posts about the DiNotte AA battery holder having corrosion problems.

My MagicShine didn't fail due to water because it never was on the bike long enough to get rained on! I really don't know why it failed. I think it was the charger because the battery would no longer hold a charge for more then 10 or 15 minutes, but maybe the battery had an issue. The battery never got hot enough to burn like the liability claims for fires are about.

I've had all kinds of water related failures - but not due to "light heads" so much. I've had Dinotte battery fail due to moisture after being a really bad thunder shower. But yes, on the other hand - the lights have continued to work.

In the past - I've had Cat eye front and rear lights fail as well Vista lights and some others.

But no - I have not had a MS or Dinottee light head fail yet. (due to moisture)

I had a MS tail light fail after being in long rain ride.

It is hardly "BS" to tell people flash lights are more water proof than other types of lights. It's common sense - and the truth.......

One of my customers had a BikeRay IV literally fill up with water and fail during use in the rain, which is why my lights (DesignShine) got "waterboarded" over on MTBR (link posted earlier). If it were me, I'd want to know that my lights were waterproof and not merely water-resistant. The power cord entry on the MS lights is definitely far short of waterproof. Corrosion over time can become an issue. So, although I'd agree, the majority of the time, water won't be an issue, there are always those exceptions to the "rule."

I've had good luck with waterproof headlights -- Cateye, Cygolite, and of course BuMM, all work well through downpours.

Less luck with tail lights. I've tossed a Planet Bike tail light because of moisture intrusion; the switch corroded. NR Cherry Bomb failed too; I don't know what happened but it doesn't work after the first good downpour. Cateye taillights have survived those showers while adjacent to the failed PB lights, and more; but I've also lost a Cateye and BuMM that fell apart crossing railroad tracks and shattered.

I'd split my money and buy two Cateye tail lights -- you've got a better chance of catching the batteries draining before they quit, they're relatively cheap, and they're good enough.

I never had a problem with Cateye lights either, and I love Cateye customer service-top notch all the way. The Blackburn Mars 4 so far has held up to rain with no problems, but they lied BIG time about battery life. And my Vista Xenon light is 18 years old and never had an issue with water and it's been through a lot of rain as one could imagine over 18 years. Planet Bike Super Flash just stopped working after 5 or 6 months, I sent it back for warranty and never heard nothing, sent e-mails-nothing, called and no help, so much for customer service.

I never loss a light ever, in fact all the lights I've ever (except the PBSF) bought I still have and they still work, though not sure what happened with the PBSF. I did have problem with a cheap pair of bar end lights that used those button bats one just stopped working, so I replaced those with the Soma Road Flares...those things are fantastic and very bright.

I have a Nite Rider Sport, it uses a 10 watt 6v halogen bulb, sealed in ,
and a 5 D cell , screw cap closed, battery pack .
NiMh batteries, with a long amp/hr capacity,

They also use the same light for Diving, that should be waterproof enough
for any cycling.