Pros: Bulb Durability, Battery Life, Durability, Brightness
THIS SHOULD BE ON EVERY KEYCHAIN!
I've had several of these for a few years. They have unbelievable power and three settings for battery life!! First-a Lithium CR123A battery, not an alkaline that will corrode in the heat and ruin your equipment, and usually with a ten year shelf life-never buy cheap no-name lithiums, they start fires! The light turns on with a turn of the bezel-so a little Bag Balm or Vaseline will reduce friction. I keep them a half turn away from being on and have never had accidental turning of it on. My wife, Mother, friends and I keep one on keychains. Ever been in a building with sudden loss of lights and need to get safely out? Whether it's a dark egress from a building, getting to the car in a dark parking lot-and yes, 170 Lumens will BLIND any prospective attacker, he can't even aim or drive if you've nailed his pupils! Each turn off then on gives you another power level. It can go low enough to use discreetly and not blind you. I've had a Streamlight Keymate just die without much use before, never had any Fenix fail me yet. Several of my firearms even have Fenix lights on them, one is a PD 32 with the red filter as a back up/navigation light with the red lens. It's on a 5.56mm Kel Tec PLR-16 'pistol', and a TK-35 is on my Marlin 1895 Guide Gun lever action .45-70, so I'd say they are durable! I also have never had any noticeable parasitic drain of the batteries on any of them-off the top of my head I'd say I have ten different Fenix lights, not counting gifts, about five Streamlight and six SureFire, and have worked night shift almost exclusively in Military Contract Security and Corporate and Law Enforcement-so I know my lights. LEDS almost never fail. Krypton, incadescent, Xenon and halogen can go out at the worst possible times!