Fenix E0 Dart
The Fenix E0 affectionly known as "Dart" is a single cell AAA flashlight powering a 5mm Nichia LED. The flashlight is designed for runtime and usability and not to be a bright white wall hunter.
The flashlight is extremely small and suitable for keychain carry, barely bigger than the AAA cell that uses, the twist is a simple twist on/off switch the neck of the light having a protuberance that helps the on/off mechanism and the switch, being construced with HA-II aluminium the "Dart" can be kept with keys and other items without damaging the light, it will resist impacts and scratches and it is water resistant using o-rings for sealing. The light can stand on its tail and be used in candle mode for room illumination. In the box it comes with a split ring, a lobster clip and some spare orings.
The light is powered by a single AAA battery and can use alkaline, rechargeable or lithium cells. It has a circuit to regulate the output so it will offer aproximately 9 hours of fully regulated light followed by about 11 hours of a dimmer moon mode so the total runtime with a single cell is aproximately 20 hours. The flashlight is not bright, but is designed for runtime and not for brightness. Comparing it wiht the Arc AAA-P the E0 is dimmer and bigger but the cost is exactly a half so it becomes a serious competitor. It doesn't come with a pocket clip but you can order one for $2 from Lighthound.
If what you want is a keychain light that has good runtime without caring for the brightness then the "Dart" is a very good deal for the money, you have more expensive premium options and brighter options but this is a value for the money deal to consider.
You can order from Fenix-Store or Lighthound for $20.