What I know about antique glass bottles wouldn't cover both sides of a matchbook. But here are some excellent links on the subject, so you too can learn the difference between a pontil and a blob:
Miscellaneous Links:
Right: Plastic Coke bottle with screw top
Computers and electronics change so fast it is hard to keep up with it. The general recommendations below should hold up pretty well even as the technology races forward.
The dive computer should be considered standard equipment. Diving with a computer will give you more bottom time and more safety margin than crude estimating with dive tables. If you are buying your first set of gear, get a computer rather than analog gauges, and you will not regret it. There is a great deal of variation in the design and operation of dive computers. Among the choices you can make are:
More: Gauges & Computers ...
