I'm still EDCing (for like 10 years) the discontinued Photon Rex on my keychain http://www.photonlight.com/discontinued-products/photon-rex-li-ion-rechargeable-led-flashlight/ the primary woner of it is that it helps me to fully utilize every alkaline battery depleted below any other device voltage requirement. This little vampire can feed on any 1.2 - 3V type battery or accumulator, sucking it to a zero. Also I have a coin sized powerfull neodymium magnet glued to its back, so I can attach it to many steel points I have integrated into my clothing over the time, or use it as a simple compass on a string. The ingenious tiny magnetic charger is riding on the same split ring (picture is not mine).