The best way to tell a cave diver apart from an open-water diver or cavern diver is to look at the equipment in use. In this section we'll look at the different kinds of gear a cave diver brings on a dive.
It's important to remember that cave divers carry redundant equipment -- this means that for every piece of equipment they carry, an extra will come along for the dive. This is to make sure that if something undergoes failure, there's a replacement to take over and allow a safe return to the surface. It could be something seemingly unimportant like an extra mask, or a piece of equipment that ensures a diver's survival, like an oxygen tank.
While open-water divers usually use snorkels because they can easily reach the surface for air, cave divers could never afford to bring one along and have no use for it. Cave divers stay submerged in the water for long periods of time, and therefore bring along oxygen tanks for breathing purposes -- a snorkel would only create excess weight and extra drag.
Cave divers usually keep masks simple, preferring standard masks that are solid black. The reason dark masks are well suited for cave diving is because of the light-absorbing qualities of the color black. Any distracting light that might leak into the mask can be absorbed by the dark material of the mask and prevent a diver from losing sight of entrances or important spots. Cave divers also wear hoods made of nylon to protect their heads from water leaks and damage during dives.
Cave divers typically prefer black rubber fins, and ones that aren't very flexible. Light, stiff fins work best because divers already so carry much mass with them into a cave. Moving through the water, they need to use short, controlled kicks to avoid stirring up any sediment on the floor of a cave.
Cave divers use either dry suits or wet suits for protection. The difference between the two kinds of suits is that dry suits are designed to seal off water from entering and getting a diver's body wet. Made of a synthetic rubber called neoprene, dry suits are the preferred choice for cave divers because they allow much less heat loss. The material is double-layered with a small space in between for insulating air, and divers have the option of wearing extra undergarments. Wet suits will still suffice for shorter dives and warmer waters, however.
Other equipment such as flashlights and small knives to cut away snags come along on a dive. There are also several gadgets that help divers during their ascent and descent. Different gauges give information on air pressure and depth, and they may all be fitted onto one device along with a compass for navigation.
Cave divers, of course, need to bring oxygen tanks, or cylinders, with them while underwater. To learn about breathing in deep, high-pressure water, read the next page.