In a cave, light is right below oxygen in your priority of needs, for without light, you are not getting out. A reliable light source (or better yet, three of them) is the most important gear a spelunker carries.
Outdoor and paramilitary suppliers offer a wide range of high performance flashlights. Seek lights that are, in order of priority, bright, durable and easy to manage. Performance is far more important than price; your life depends upon this light.
Three light sources, a minimum
Carry, at least, a primary light source, a secondary light source and an emergency light source. These should all be real flashlights. Your cellular phone does not count. When you are down to the emergency light, it is time to find the exit.
Cavers typically use a headlamp as their primary light source, ideally fixed firmly to a helmet. Carry a bright, high-performance flashlight as a secondary source, and a small, durable flashlight as your emergency light.
There is no such thing as too bright a light in a cave. Since your alternative is utter darkness, preserving night vision is a non-issue. Although technically, high-end incandescent lamps are still the brightest available, LED lamps generate 80 percent of the light output with 10 times or more the battery life. LED's do not have filaments, and will not burn out in the lifespan of the headlamp itself.
Durability is as important as brightness. The warranty on a flashlight is a fair indicator of its reliability. Your headlamp should be at least water-resistant and your flashlights should be waterproof.
Don't skimp on batteries. In general, bigger batteries last longer than smaller ones. Lithium batteries last longer than alkaline batteries. Buy the best batteries available, and bring extras.
Look for switching mechanisms that will turn on and off when you want them to, and at no other time. Avoid products where changing batteries is complicated, or worse, involves loose parts. Imagine having to change batteries in the dark, because that could easily happen.
LED Headlamps are now available that put out at least 100 lumens with at least 12 hours of battery life. That should be your minimum standard. A head that can tilt to multiple angles will be a great convenience. See that the straps are thick enough to take some abuse. Weight and features like multiple colors or settings are not important. You are going to strap this to your helmet (you're wearing a helmet, right?) and leave it on bright for the duration.
Any handheld flashlight that you take into a cave should have a long, sturdy lanyard and a bomb-proof belt pouch. Flashlights that throw a brighter beam farther out can be handy in a long passageway. The secondary light should have a focusable lens for that reason.
Article Written By Tony Padegimas
Tony Padegimas is a freelance writer based in Phoenix. His articles on outdoor pursuits, general fitness, sports, theater, the inside guts of buildings, and many other random topics have appeared in numerous local and national magazines. He is the author of Day and Overnight Hikes - Tonto National Forest, published by Menasha Ridge Press.