Excellent product, still going strong!!!
355628
To answer my own question -- yes, indeed, this will charge EITHER a Kindle Keyboard OR a Kindle DX (I do NOT recommend trying to charge both at the same time!), without ANY trouble at all. I've only had to recharge the thing twice since I got it, and that was merely to top it off -- I could very easily have gone without recharging it at all, and my guess is that it would only NOW just be starting to get low on charge, and even then would still have plenty of power to fully charge up both of my overflowing Kindles.

No one should hesitate to buy this backup battery. The only real concern is the charger: some of these are cheap, or have the wrong components, and can overheat badly. If this happens to you, seek out a better charger -- but the battery pack itself is WELL worth the purchase price!!!  :)
1000119
I have been using this for about 2 years now and it is still working just perfectly! I definitely recommend this product and would buy it again in a heartbeat.
851598
I ordered the product almost a year ago. The product is still running and we use it every day. Very happy!
1454198
I've owned this for a while now and it's still going strong! I have a feeling I'll be using this for a long time.
3459634
Very well built... bought it a year ago and still going strong!
34818
Love it so much! Been having it for months now and its still in great shape!!!
3929336
Excellent product thus far! Highly recommend them!
3356374
*****  UPDATE JANUARY 2016 *****

This sticker is still going strong! I had to buy a new one for my new truck and I fully expect this one to last three years as well.  Great product.
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This installed in mere seconds on my new car - no problems at all. I just cleaned the window first with some Windex, let it dry and then put the decal on. Done. It's been on for about 90 days now in temps ranging from 102 in direct Texas sun to our first fall cool snap of the low 40s in rain. I've run it through 3 car washes - one with brushes and two of those touchless things and the decal has held up just fine. No fading or peeling at all. One of our neighbors ambled over the other day wearing his cunning Jayne hat to give me a thumbs up when he noticed the Firefly sticker - all these years and I had no clue he was a Browncoat!!
1047921
Very good product, consistently reliable. Great price!
874340
Excellent, excellent will be ordering more, works perfectly and lasts long!!!! Thank you!!! I would totally recommend it and can't wait to order more!!
2541056
I have bought this product twice: In October 2016, and in December 2017.
Here's an updated feedback based on both purchases: After more than a year of taking heavy wear, such as countless falls and the like, my old DBPOWER that I bought in 2016 is no longer working properly. In all honesty, had I bought the extended warranty offered by Amazon, it probably could have been fixed.
I still rate this product as excellent and a good value, so I bought the exact same product without thinking about it twice. I have never had an electronic gadget taking so much falls and still working like nothing happened (screen in good shape all the time).... so 14 months of heavy use is reasonable, to me.
The new unit that I bought in December 2017, features some updates in its interface. The device itself seems to be slightly "thicker" in its dimensions, but it still fits my old DVD holder, so that works. The buttons have a more refined finish, and they feel better, too.
There are a few other modifications in some of the accessories, but the overall quality seems to be as good as the previous version, so I am a happy camper. This time I bought the extended warranty offered by Amazon because we are tough users.

All in all: I am really impressed with this unit. It can even play partially scratched discs other DVD players failed to recognize, so I really value that!
470149
Almost a year of daily use and still going strong
2658126
I was very pleasantly surprised with this.
This product works extremely well. I have had it for over a year and it is still going strong. I have never had trouble with it at all and for the price I would buy more in the future.
680693
Excellent product, brought my old makita drills back to life. I bought some of these batteries before just to try them out and they are still going strong!!!
1066304
Longer then expected but still a good product!!!
773209
So far excellent product, I hope it lasts

---------- UPDATE -------------

The company I work for has a no tail gating policy, so I use this a looooot of times during the day, 1 year, 8 months later this thing still working perfect!!!!!!!!!!!!. Reeeeaaaaaally nice product
277255
I was so excited to find this product is still being made!!