This is my favorite light. I've bought two. I have Maglights and LED Lenser, among others, and these are great. But this little, single AAA flashlight is a very bright pocket light that just works better and brighter than any other light in its size class. Unmentioned in the product description, the power button, as well as the edges of the glass lens cover both glow slightly in the dark which makes it easy to find if you drop it in the tent or on the trail. I also put an Ultrafire 10440 500mAh 3.6V Li-ion battery in it and it got even brighter. If I didn't fantasize about million-lumen handheld light cannons, I might be tempted to say this is the only flashlight I'll ever need.

I started my EDC adventure with the Avenger ( approx 50.00) I switched over to the LM21 at 1/2 the price and have been very pleased.
Over the last 8 years, I've bought no less than 20 of these lights. 10 were gifted to groomsmen at a wedding..(What a hit, I also provided 2-UltraFire 10440's and the 4.95 USB charger)
I have 2 Air Force pilots in the family who LOVE this light. Super bright and not bulky. DOES get warm on HI, but seems to take it just fine.
Per other reviews, the rubber tail SW is the definitely a miss-step in engineering.
I also could not get the TrustFire (TR10440 ) to work in this light. The LM21 will work on a standard AAA battery, but is far and away better using the UltraFire Lithium battery.
Another PLUS .... you can hold this in your mouth and use both hands and your jaw won't cramp. ( sure it looks odd, but sometimes you need 2 hands. A fatter flashlight is very uncomfortable and you look really weird - yea, don't do it. )
To control light spread, I hold it I'm my fist and select LO. Then I use my little finger to partially block the output, that way I can look at a program at the Opera without disturbing others.
And finally, I ordered 3 more of these in June of 2019 and they were B/O for 3 months.
I've already re-ordered 3 more of the 8 they have in stock.
I actually use this light hard enough to wear them out. If not the tail switch, then a broken lens, to the head going bad (which zaps a charge out of your battery in short order)
Buy this light before someone decides to stop production. You won't be disappointed .

I have purchased several of these lights as well as some other single AAA versions built by other manufacturers (O-Light, Coast, Streamlight). I like the LumaPower LM21 better than any of the other ones for the following reasons: small size, quality fabrication, 3 mode lighting, no strobe, decent pocket clip. But, a big but, each of the LumaPower LM21's, without exception, failed after a few months of use, due to the switch breaking. First the rubber cover over the actual switch is fabricated from a much too soft of rubber/silicone/whatever it is material and the cover will rip off and expose the actual plastic switch actuator (see pics). The rubber rips, not from abuse or even use, but from being carried in one's pocket, which is what the light is designed for! The actuator under the rubber cover is recessed into the flashlight body which causes it to be a pain in the rear-end to actually manipulate the switch. After a short while of the internal switch actuator being exposed due to the rubber cover ripping apart, I'm guessing, dirt, dust, lint, or something causes the switch to stop operating properly (sticks in the on or depressed mode, like a cheap pen), eventually rendering the flashlight useless with the switch either stuck on one of the on modes or off completely. It is too bad, because if this flashlight had a decent switch, and/or a decent warranty, it would be a five star light all day long. I probably will buy more of these, because I really like the light, I carry it and use it every day, but, with a bit more quality control, this light would annihilate the competition! Not sure if the manufacturers actually read these reviews, but if so, consider redesigning the light so a person could purchase additional rubber switch covers and make the flashlight so it can be disassembled a bit so a person could replace said rubber switch cover when it rips... Thank you for your time.

First of all, I MUST comment on the review that said (I'm paraphrasing)" this light doesn't put out 300 lumens on a AAA". That's the EMITTER lumens with a 10440 battery, which addresses the comment that 10440s won't fit. Hmmmm....I have 3 different brands of 10440s that fit just fine. The ONLY 10440 I have that WON'T fit is a Trustfire protected cell. This light was the reason I got into EDC AAA lights - I currently own 5 10440 lights, and this one has been through some abuse and still works just fine. I really like Ricky at Lumapowers Customer Service - he'll actually respond to emails personally. Good luck finding another lighting company that does that.... go ahead, I'll wait..... yep, that's right, there's not many! I also like the knurling on the upper barrel - if you're using this as a tactical light, it helps with grip in between ther fingers. The beam pattern is quite floody, but with a decent corona and good throw for a teeny light with a teeny reflector. All in all, a reasonably priced AAA EDC that works as advertised.

Just because it's small doesn't mean it can't get the job done. The lowest setting is good if you're trying to get around in the dark without waking family members and don't want to step on the dog! The medium setting is enough light to walk the dog and on high you can see what the dog leaves behind long before you step in it. All that with a standard alkaline battery in it. You're not going to use it for search and rescue, but it packs a lot of function into a very small package.