Lumintop GT Nano (Black)
Skemer's review of the GT Nano:
It's simply mind boggling to think that something that hangs on a key chain (at a full 17 grams!) and would be shorter than 99% of the keys on that chain is able to throw a spot of 300m, but the 450 Lumens GT Nano does that and does it exceptionally well. It supports the Uncle Tom E's GPL NarsilM, which amongst a host of settings and options allows for smooth ramping which a personal favourite - tailor you lumens to your exact liking instead of being limited to the normal 4 or 5 step operation. Simply put, this very tiny light outperforms, spot-wise, alot more expensive and a much larger flashlights on the market.
Emitter: OSRAM KW CSLNM1.TG LED, Cool White
Flux: 450 lm
Throw: 300 m & ~23400cd
Firmware: Tom E’s open-source GPL NarsilM v1.3
User interface:  By default the GT Nano is set to use the very intuitive Narsil smooth RAMPING UI. Instant access to a 2.5A TURBO mode is also provided.
 A more conventional discrete level MODE-SET UI is available as an alternative. Any one of 12 pre-defined mode-sets can be selected.
 MOMENTARY mode is useful for signaling purposes or rapidly/briefly lighting up targets.
Battery: One button-top 10180 Li-ion (included).
Driver: Texas Avenger FET driver
Reflector: 20.8 mm ID, aluminum, smooth finish
Lens: Glass with anti-reflective coating
Body: Aluminum with Type III hard-coat anodizing
Button: Tactile with back-lit rubber boot
Ingress rating: Equivalent to IPX-8, underwater 2m
Weight: Approximately 17g without cells
Dimensions: 24 x 52.5mm