The light is solid titanium, which heatsinks about 1/10 as well as aluminum. The l.e.d. is a R5 bin Cree XP-G (135+ lumens/watt). The P1Ds and P2Ds have only been upgraded to Q5 or R2 bin Cree XR-Es or XP-Es (about 100 lumens/watt). I have a P2D Q5 which is rated at 180 lumens, but it's more like 150 lumens. The PD10 R5 Titan is about as bright as (if not a little brighter than) my P3D Q5 which I remember being tested at 200-205 out the front lumens. 216 lumens seems about right for this light. Low has been my most used setting. However, I don't think it stays at the exact same brightness on low throughout the battery life. I think mine started at about 30 lumens for about a minute, then dimmed down to around 12 lumens. After I used it for longer durations, the low seemed dimmer and at around 7 lumens at which point the brightness stayed constant. The light is pretty easy to turn on with one hand, but if you put it in your pocket, lock it out well because it can turn itself on and get hot quickly. I have found that the easiest way to change levels is to have the head turned to where it is almost on: push down on the head, let go of the head. Repeat these two steps until it's at the level you want. When at the level wanted, keep pressure on the head and twist the head into the on position. I think you'll like this light. The beam pattern works great for the outdoors. It has a tight brighter hotspot inside a large hotspot, with bright spill light. At close range on low, it still lights up the trail and shines a good 30 feet ahead. Due to it's beam pattern, It is useful for close, midrange, and far distances.
