Poe wrote:

> Once observation; with the DIN, you can unscrew the first stage
> with a bit of pressure left in, and that unseats the O-ring.
> Had someone lose his that way two weekends ago (fortunately
> it was still in the previous tank). Anyone else noticed this?

Well, you can probably unseat a yoke valve o-ring the same way if you try
hard enough.  I have 6 DIN regulators and I've never unseated any o-rings
doing what you describe. My first suspicision would be that your friend
didn't have the correct size o-ring on his regulator.  Smaller gauge o-rings
will still most likely provide a seal but they will fall out of the
regulator more easily than the correct size.

One advantage to DIN is that the o-ring is YOUR o-ring on YOUR regulator
rather than some grimy old o-ring that's been on the same rental tank for
years, sitting in the sun, getting dried out cracked and nicked etc. etc.
Not that o-rings fail often.  But with DIN this is something you have
greater control over.

By they way, the Scubapro brand hose protectors come with a handy o-ring
retainer for spare valve o-rings.  Most people it seems don't know this.  On
the sides of the Scubapro hose protectors there are circular grooves that
are designed to hold spare o-rings.  They actually stay in there pretty well
and it's a perfect place to store a couple extra o-rings.  That way you can
actually replace a leaky o-ring in the water.  I did that once while
floating on the surface on a shore dive.  Saved walking 1/4 mile back to the
car.

-Kent-