A small keychain LED flashlight is extremely useful because it’s the light I most commonly have on me. Everywhere the my keys go, the light follows. Therefore, it’s important that the light on my keys should be reliable and versatile, while keeping the bulk and weight down, otherwise I’ll be tempted to leave it at home. The followig are my top favorite keychain flashlights.
The Fenix E05 (2014 model) runs on one AAA battery, but has 3 output levels, making a versatile light. A low mode is useful if I need a low output to not disturb other people, minimize glare, and gives up to 14 hours of battery life. The 85 lumens high output is useful to walk around in the dark outdoors, and see farther than 20 feet ahead that your typical phone will illuminate. The medium mode is a balanced all around combination. I also like that the Fenix E05 uses a TIR optic lens, which provides a smoother, more even beam than a typical reflector.
The MecArmy Illuminex-4 is a small light with big capabilities. It runs on a tiny 10180 lithium ion cell, has a built-in USB charging port, low and high output modes, and an awesome user interface. It turns on in low mode by twisting the head, and twisting it further switches to high mode. Thus it’s easy to switch between low and high output levels without turning the light off. The battery is a standard 10180 cell, and can be replaced. This is much better than a light that uses a non-removable, non-replaceable battery that eventually wears out and makes the light worthless. The MecArmy Illuminex-4 also uses a TIR lens, giving it a smooth, pleasant beam.
The tiny LRI Photon Freedom runs on two CR2016 lithium coin cells, but packs many smart features. The light output is variable from low to high, and you can start in either low or high mode directly. There are also several strobe and beacon modes hidden out of the way. The CR2016 batteries have a long shelf life, do not leak, are commonly available, and you can even carry spare batteries in your wallet. This is a good choice when you want the smallest, lightest flashlight on your keychain, with no maintenance of charging batteries, but still having a real flashlight and not a gimmicky toy. As a bonus, the Photon Freedom also comes with a neck lanyard and a magnetic swiveling alligator clip, giving you extra versatility in using the light.