Posted by Jason on October 02, 2000 at 12:18:11:
In Reply to: Octopus on scuba rigs posted by isidoros on October 02, 2000 at 08:51:25:
Is that a serious question? Are you a diver?
To provide a second means of breathing off the tank,
either because the primary fails, or because you need
to share your air with your buddy.