Brite -Strike APALS .
I was first sent one of these great bits of kit by Andrew from Valley deep mountain high http://valleydeepmountainhigh.tumblr.com/ about 2 years ago and found that for their size and versitility they are invaluable items to have if you need to be seen or to see in the dark especially when partnered up with other flaslights or illuminating kit .
The latest versions apparently have a 200+ hour runtime , can be seen up to a mile away and have 2 strobes and constant on / off ability with a 3M adhessive pull off tab that allows them to be stuck to many types of surfaces .
In use the APALS is supplies enough light to naviagte a small room , read or check a map by as well as a great marker for personal or kit use to find your gear or team mates in the dark .
This white one was kindly sent to me by the folks at http://www.survivaldepot.co.uk/product/apals who I beleive are the only place in the UK that are currently selling them individualy rather than in standard packs of 10 of the same colour .
Full specs here http://www.brite-strike.com/APALS.html