A helmet needs to fit well and include a fitted chinstrap. The common electric light is often battery powered and not rechargeable. This light is either confined to your helmet or split between two pieces of equipment with the battery pack usually attached to the waist by a belt. Another lighting device is the carbide lamp. Carbide lamps provide a more diffused yellow light rather than the white spotlight produced by electric lamps.
Carbide lamps burn off of acetylene gas produced by a constant water drip on calcium carbide.
This lamp casts light using an open flame and one must take precautions with this flame. It is recommended to switch to an electric light source when vertical caving. A plus to carbide lamps is its use as a heat source. Within about five minutes a mildly hypothermic person can get warm by placing a carbide lamp under a garbage bag which they are inside of with only there head outside the bag. Just remember to watch the flame when it comes close to the garbage bag.