A diving torch
There are additional hazards when diving in darkness, such as torch or flashlight failure. This can result in losing vertical visual references and being unable to control depth or buoyancy, being unable to read instruments such as dive computers and diving cylinder contents gauges, and potential separation from the rest of the diving group, boat, or shore cover. Even with a functioning torch, these hazards are still present in night diving.
Normal requirements for night diving are a torch/flashlight, proper protection from exposure, and use of a strobe light. Some precautions and skills for night diving include: avoiding shining your light in other divers' eyes, to be aware of and use surface light signals for bearings, or similarly use a surface marker buoy with an attached strobe or cyalume stick.