11.   The POD runs on batteries, is about the size of a coffee mug, and can be clamped to a scuba tank or built into a surfboard.

12.   The popular form of diving taught in many resorts employs scuba tanks and a regulator to supply compressed air or a mixture of gases to the diver.

13.   The systems are quieter than conventional scuba tanks -- important whether one is eluding enemy subs or photographing clown fish -- and they allow for longer dives.

14.   They are sport divers preparing to plunge without scuba tanks into the frigid, kelp-blackened Pacific Ocean in search of abalone, a legendary local delicacy.

15.   It is about the size of a scuba tank.