Good basic EDC light
First, If you are looking for the brightest, farthest thrower, turn night into day flashlight on earth this is not it.
This light is a great little light for an EDC or backup to EDC light. I have around 6 of these and will probably buy a few more. I leave one in each jacket pocket I wear (so I don't have to remember to switch the light to whatever one I am wearing). Also great for small survival kit. Some people like them for keyring lights.
It outputs around 10-13 lumens for the first 7-9 hours or so and then dims to a still usable light outut up to the rated 21 hours or longer depending on battery type used. That is a lot of usable light for doing tasks, even fallowing a trail. etc.
This light is 'vampire' light which means it will drain the cell down to almost 0 voltage. This helps to contribute to the long burn time. But if you use rechargeable (like Eneloops) it is not good for them to be drained down that low so when you see it dim, replace it and recharge that cell. I use Eneloops for the lights I use often, or Energizer Ultimate Lithiums for the ones that mostly sit, like emergency kits etc. ( I stay away from alkaleaks )
The one downside about this light is the beam pattern and color, most have a blueish / purplish somewhat hourglass shaped hotspot, with a yellowish ring around that. So what some people do (if this bothers you) is to lightly scuff up the plastic on the LED itself by rubbing it with 0000 steel wool, or even a green scotch bright pad. This defuses the light somewhat , so the colors blend and it makes it a much nicer overall tint and is then more floody beam also. This works great if you usually use your light for close up work, tasks etc. Maybe not so great for seeing very far down the trail.
To wrap it up, one of my favorite little lights, nice small lightweight size, easy to carry and always have one with you. Nice long usable runtime and not super expensive - so you can buy a few of them and stash them in convenient places.
Decent key chain light
Flashlights are always a balancing act between size, runtime, and light output. Understanding this helps in choosing one you'll be happy with.
The EO1 is small, lightweight, fairly durable, and has a good runtime (battery life). It's not super bright, but puts off enough light to get you around in the dark. It will light up the inside of a small room or tent enough to work. You can easily read by it. Decent for what it is... a key chain light. Many keychain lights run on coin (watch) batteries. I think AAAs like this one are a much better choice.
My one concern or complaint is the switch. It's a twisty, meaning you twist the end to turn it on and off. You have to make sure that you un-twist far enough when turning it off. Otherwise if it gets pushed up against something in your pocket, pack, etc. that will turn it on and drain the battery. Not a big deal, just be conscious of it. Also if you turn it in the wrong direction too many times it will unscrew the end. Takes several full 360 degree rotations and most people would figure it out before that happened, but some people aren't very *bright* when it comes to even simple mechanics.
I normally carry the Fenix E11 which is substantially brighter and has a tail cap switch. It uses a AA battery so it's bigger than the EO1, but still small enough to carry in your pocket. However, it has a much shorter runtime.
I purchased several of these EO1s for gifts. Being used to a much brighter light I was concerned they would not be very useful. That isn't the case. In fact there are situations which they're better because they don't disturb your natural night vision as much. For someone with exceptional difficulty seeing in the dark a the EO5 is a brighter AAA keychain light, but it has a much shorter runtime. For most people, however, the EO1 will serve them well.
Fenix makes good lights. I'm glad REI sells them. If you think about your needs and make your choice accordingly, you'll probably be very happy with it.
Perfect for the emergency backup
First of all, forget about all the bells and whistles that you see on other flashlights. In an emergency you just want a light that is 100% dependable. This light about as dependable as flashlights get and lasts for as long as you are likely to need it.
The LED is one of the most efficient you can buy and so is the driver circuit. It will run all night and pull every last bit of juice from your battery (driver circuit delivers full power down to 1V and partial power down to 0.3V of battery voltage) The whole LED/driver circuit is encased in epoxy and is completely waterproof. 13 lumens doesn't sound like much but when your in the woods at night it is plenty to see the trail and find your way home.
Check the internet for mods and you will see that to remove the LED from the case usually involves a vice and hammer (and it still works afterwards!) Nobody has ever claimed to accidentally break one.
I carry mine in a pocket of my pack with a Energizer Li battery so that it is always ready. The few times I have had to use it to find my way back after dark it worked perfectly. It weighs next to nothing with Li batteries so I always have it with me when hiking.
Good little light, powerful for the size
I ordered this to have as a small light on my keychain, for the times when I need a little extra light such as unlocking my car door or the house when the porch light isn't on. For it's size, it's very bright and will light up a decent sized area. It's lightweight and hardly noticeable when my keys are in my pocket. It's come in very handy several times, and it's nice to know I have a little extra light when I need it.
Great little light
This light is designed as a keychain light so you can find the lock in the dark. However, it works amazingly well as a backup light when backpacking. And if you are trying to lighten your load, it will even function as a primary light. It's surprisingly bright. It's much more functional than the pinch lights that some ultralight backpackers recommend.
FENIX FLASHLIGHT FAN
This just might be your favorite flashlight. Not a AAA battery fan, but could be worse to use button cell batteries.Better than those mini keychain flashlights that you need to keep pressed down. Hopefully you won't loose it on your keychain. You have bigger problems loosing your keys...lol.
Great little light
I actually bought this to use as a pen light to do physical exams with. I am a medical resident and actual pen lights break when you drop them. This thing is indestructible and very bright. Now I use it for everyhting.