Night Diving Requires Primary, Marker, and Backup Lights

Night diving is a form of recreational diving that is growing in popularity. Divers enjoy nocturnal adventures because many sea creatures are most active at night.
But night diving has a lot of risks. Scuba light failure can be the most dangerous, because the diver can lose his or her bearings and cannot monitor gauges. The diver can become separated from a diving group, a dive boat or drift farther from shore.
The protocol for night diving is to carry three dive lights -- a primary light, backup light and marker. Divers use a larger light with a broader beam as their primary light. They have a flashlight or smaller pocket light as their backup. A marker light is attached to the diver - usually near the tank valve - so he can be spotted when floating at the surface.
Although not required, divers may also carry a strobe light, which is used for a signaling device. Strobe lights can very helpful to a diver lost at sea.