I agree with Chris on the Photon 2. I have carried mine on my keychain in my pocket for over 2 years - it is reliable and seemingly indestructible. I use it regularily and I am still on the original battery! <br><br>I chose the green for it's 200 hour battery life - mine came with the large single cell - the greens are now sold with the 2 smaller cells making it much brighter but cutting the battery life to under 20 hours. However, you can still retrofit the green with the single larger battery to get the 200 hours.<br><br>I don't have a Photon 3, but people I know who do have one, say the increased complexity has sullied the perfection of the Photon 2's design - especially concerning are accidental turn-ons that sap battery life.<br><br>The Photon 2 is one of my all time favourite tools - highly recommended!