What with the camping, canoeing and fair-weather bushcraft season here, I have been on the lookout a flashlight with a good power output. My collection of AA powered Fenix lights are great, but not quite what I wanted. Following a long look and plenty of reading, I decided on the TK15 powered with two CR123A?s or one 18650 rechargeable it delivers a whopping maximum output of 337 lumens, believe me this baby is bright! Before you read any further I will admit that after owning many flashlights over the years I have become a big fan of Fenix, they are always my first port of call when looking for a new one. Using the Cree XP-G R5 LED (50,000 Hour life span) provides high intensity coupled with very effective energy conservation giving a variable output of 5 ? 337 lumens in four stages. The 23.5mm deep-dish reflector gives a working focused centralised beam throw of 215m on maximum power with a nice wide beam spread. I love the orange O-ring seal. A light press of the end cap switch affords momentary on/off of whatever power setting you choose, with a firm click for on and off . Then you can choose from 5, 47, 143 and 337 lumens using the silver side button, with a one-second press of this switch activates the rapid strobe. The last setting used is memorized ready for your next use. I must say that this method of output selection is much easier to use than the twisting of either end, as I need to do with my other Fenix lights. A big thumbs up for this development. This tree is about 180m away with a bright full moon. What is mind-blowing is the battery life running two CR123A?s the following run times are achieved: 5 lumens = 142 hours. 47 lumens = 23 hours. 143 lumens = 6 hours 25 mins. 337 lumens = 1 hour 50 mins. The TK15 has dual recoil absorbing springs this helps absorb any shock and makes a much more robust flashlight for firearms use. There is also an optional remote pressure switch and gun mount available. It is impact resistant to 1.5 meters. The hard-anodized finish gives great anti-scratch resistance, I have had an LD15 on my key ring for a long time and it?s weathered very well. A really strong pocket clip and tactical grip, both easily removed if you don?t like them complete this very capable and very impressive flashlight. Dimensions: 135mm (Length) x 25.4mm (Diameter) x 34mm (Head) Waterproof to IPX-8 Underwater to 2 meters. Webbing pouch, two spare O-rings, lanyard and an orange rubber switch boot come with the TK15. I will keep you all updated on with any changes. One thing I will be ordering is a pair of 18650 rechargeable batteries and charger, they give a longer runtime and will save money on the long term. I will publish my findings on these once I have used them a few times. This was purchased from www.thephotonshop.co.uk with super quick service and free delivery you can?t go wrong. No connection, just a happy customer. UPDATE As I said, I was considering the rechargeable battery option, so here they are. I bought the 17670 / 18650 Dual bay charger with two Trust Fire 2400 mAh 18650 lithium batteries. http://thephotonshop.co.uk/page44.htm Straight from the pack, neither battery would power the flashlight, so popped them on charge and approx. three hours later the red charging light changed to green and off we go. I was asked if the power output was less with the rechargeable?s than with CR123A?s. IMHO I would say no. It is difficult to be exact as I cannot measure the output nor do I have two TK15?s side by side, but I can say that after leaving them running for 10 mins on both types of cell I honestly could not see a difference. The rechargeable cell?s win it for me due to their prolonged performance and the massive cost saving against CR123A?s. I also ordered the Fenix TK series camping lampshade AD502-N http://thephotonshop.co.uk/page59.htm Fitting the TK11, 12 & 15 it is a new add-on, which functions really well. Simply push this on the business end of the light and away you go, all the light is cast downward. It makes a great table lamp as the light is directed away from your eyes or can be hung from its hanging loop. It really changes the whole perspective of this flashlight, great for general use, canoeing, bushcrafting and an overhead light whilst reading in my hammock. The only thing is that in order to use it as a table lamp you need to make a stand. The large rubber sucker I used is from my local camping store and originally used for the end of a tent pole.