[Simultaneous] As I was getting ready to leave for a trip, I couldn't find my charger. I found the Jupio on the B&H website and ordered it. It arrived in 2 days, and since it works via a USB interface, I was able to use in other countries with no difficulty. It charges quickly and tells the percent of charge on the battery. Just what I wanted.

[Simultaneous] I needed a duel battery charger, it does what it says it does. Seemed like a vvery resaonable price too! Couldn't be happier as of now.

[2] I was looking for a charger that I can use to charge via a USB-C port, to take advantage of fast charging using a battery pack while traveling. The Jupio charged a single battery from just 3% charge left, all the way up to 100%, in 2 hours and 38 minutes. After 2 hours the battery was up to 93%, so it took the remaining 38 minutes to charge the extra 7%.

I also have a RavPower charger (no longer available) that uses a micro-USB port for the charger. The micro-USB specification limits the amount of current traveling from the battery to the charger, so it's not as fast. A similarly depleted battery took 3 hours and 20 minutes to charge in the RavPower.

When buying such chargers, pay attention to the current supplied to the battery. I couldn't find many chargers that can supply 8.4V at 1A to a battery as the Jupio does. For example the RavPower is rated at 8.4V and 0.7A, so it charges much slower. The other notable charger that seems to handle 1A is the SmallRig one, but it was not available when I got the Jupio.

Note that charging 2 batteries at the same time will limit the amount of current going to each battery to 0.8A, which means slower charging overall. I have not tried to see how long it takes to charge 2 batteries.

[5.1 x 3 x 1.2"] Dual charger for 2 batteries. It's what I ordered and it's what I got.

[Simultaneous] Works fast for these batteries

[0.245 lb] Additional USB port on side.
Not sure if you could do these in series through additional usb but that would be nice.
I do astrophotography in addition to wildlife both of which eat battery power.

[Simultaneous] I bought this along with two additional batteries and it works like a charm! I also use it as a quick check for the remaining charge since it doesn't require external power to do so. It gives a handy percentage remaining figure which is more than my camera can do at a glance. I haven't tried using it to charge a device using camera batteries yet nor have I really stress tested it to ensure it doesn't over charge batteries. However, it seems to be operating well so far.

[5.1 x 3 x 1.2"] These batteries are great! I use these on my on camera monitor, as well as my Amaran 60D. They work flawlessly and hold a good charge!

[Simultaneous] The batteries and charger are both great quality. No issues. Charging does take a long time (a few hours) but the batteries hold that charge well and hasn't been an issue.

[Simultaneous] I haven't had any problems. Powers my nano II control handle. Power indicators on the charger are a nice bonus, though other reviews say they are unreliable, I haven't experienced that.