This is a very handy little light that is small enough to carry around in your pocket on a keychain. The LED "bulb" is very bright for its size, more than adequate for finding your way around in a dark spot, reading a map, finding key holes, etc with simple thumb press on the button. It has a small switch that will lock the light in the "on" position. I highly recommend this Micro Light II model over the more expensive Micro Light III. The Micro III has more features, but they aren't that useful and mine used up the batteries in just a few weeks. So I bought a Micro II and have been very happy with it. The battery has lasted several months so far. 5 stars

This review is really about a better alternative to the Photon-II - the Inova Microlight. I purchased the Inova at CompUSA after doing some quick research on the net. The Inova is just as small as the Photon-II and in my opinion is a better design.

1) the case is screw-less; no micro screw-driver required for a battery change.
2) the Inova's small slide switch is easier to operate
3) the Inova's LED is recessed into the case and not exposed
4) the Inova's quick-clip is easier to attach than a split-ring.

All this at a price that is 2/3's the price of the Photo-II. (icing on the cake).

3 stars

I have extremely poor vision that gets worse in darkened conditions. I found that this little LED "flashlight" is powerful and extremely useful. It always stays within reach on my key chain, and I use it every night.
The Lithium batteries lasted me for a more than a year of hard daily use before needing to be replaced. It is very useful in when trying to see a menu in dimly lit restaurants, but remember to cover about 75% of the LED, as to not disturb others. People like myself who absolutely need to see in these settings (i.e. diabetics who need to check glucose levels at meal time) it becomes indispensable. The light is extremely useful when I navigate for my wife in the car. The light does not disturb her like the dome light.

I purchased one for a friend who is a pilot, since the red light does not effect his night vision; he now keeps an extra one on hand, just in case.
Other uses:
The red light emitted from the LED, can not be seen by deer, which makes useful for hunters in their stands while waiting for light or as backup for a flashlight.

Auto, boat, camping / hiking emergency or survival kit. The LED can be seen for some distance in the dark if looking directly at the source. If you point the light downward, the illumination is not noticeable.

The only con is that the red light does not give much contrast. I have a green light that provides more contrast, but it's hard on the eyes. 5 stars

You can find keychain flashlights on eBay for $1, but they are ridiculously inferior to this light. I've had mine for a month, and already used it several dozen times. I didn't know how handy these were! These Micro-Light II's use the newer Nichia LED's, which are twice as bright as normal LED's, but use the same amount of power (so these easily outshine most other keychain lights)... It isn't as bright as a hand-held flashlight, but you can easily use this for walking at night if you don't have access to a larger flashlight. The on/off switch also works great and does not accidentally turn on while in my pocket. I really have nothing to complain about this product, except that the price may seem high. In this case though you do get what you pay for. The batteries are two 2016 Li-Ion watch-sized batteries and are easily available at your local mega store or mall.

Beware that these are not very water resistant! I don't think water will permanently damage them, but you may not be able to get a light out of it while it is wet since seems to be no waterproofing on the case. 5 stars

As a Scout Leader, I have searched for the handiest light source available. The Photon II, although pricey comes awful close to perfect. It's small, much brighter than you'd expect, and you can take it anywhere.
It is especially effective inside the tent---I tied mine to the loop at the top and it filled the tent with enough light for conversation. It makes a great reading light, if you don't mind holding it in your mouth, and it is especially helpful late at night when nature calls.
Good feature is the snap on/off switch--so you don't have to keep applying pressure to the switch.
Bad feature is also the snap on/off switch. If you put it in your pocket on a keychain, sometimes it gets switched on and that runs down the batteries.
A powerful flashlight is the tool of choice for nighttime trail walking, but in a pinch you could use this little guy.
It's also handy around the house or in the car---anywhere you need a dependable source of light. 4 stars