> put it at risk for some cheap shit you got ........trust me i had a tank
 > that was at good price from my friend and i bought it i never took it to
 > my instructor for they could do an inspection and when i was about in
 > 20-25 ft. of water my O-Ring popped and i had to make an emergency lift
 > to the surface i got scared as crap thanks god i wasn't that deep
The quality of the cylinder has nothing to do with an O-ring.  O-rings are 
replaced very often.  When I take a group of students out from our dive shop 
(6 to 8 students), by the time we have completed our 4 tank dives over two 
days, I have replaced one or more O-rings.
Beery
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