For fast charging D300 and D810 batteries but it is able to recharging any camera battery with the proper battery interchangable adaptable plate.

This is a very nice charger, best one I have ever owned and I am 74.

It gives you the ability to charge two batteries at the same time or just a single battery. Also, you can change the battery plates to suit whatever battery you have and charge two different type of batteries at the same time.

I purchased the EN-EL3e version since it came with those adapter plates. This version was $10 less than the one marked for EN-EL15 so I was able to purchase this charger and two each adapter plates for EN-EL15 and EN-EL20 for less than the price of the EN-EL15 version. So far it has worked fine and charge all three battery types with no problems.

Awesome - I can recharge two batteries at once - great since I have 2 nikon D90's that are used frequently! I love the fact that there are two charging cords - one for household and one for the car! Since we are always on the road this is especially helpful - we used to have to bring along an inverter in order to recharge the batteries. Also like the screen & seeing how much life is left on each battery!

I immediately unpacked, plugged-in, and started testing and charging batteries when the Watson Duo arrived.

Mounting a battery with the device unplugged from power, the screen reports the percent remaining charge left on the battery, and pressing Test, the measured voltage from the battery. Finally, no more balancing VOM, +/- probes and the battery to track voltage loss!

Plugged-in, the charger reports the same information for each battery on the display, and indicates it's charging by the flashing top unit in the graphic battery indicator. Love it!!

Wanting to change battery plates, I held the charger in my hands like playing a game played using thumbs, and pushed one of the plates towards the back of the charger, like I would with any of the plates for my eight year old Pearstone plug-in-the-wall chargers. The plate would not budge! Tried the other plate on the other side of the Duo, same thing!?!? Confustion ensued, LOL!!

The manual has a minimal graphic showing installing the plate, not taking it off. So, after fiddling awhile and dismissing the use of screwdriver, it was back to thumbs pressed and squeezing hard against the corners of one of the plates, then progressively increasing the pressure applied, until it popped free! It took several similar remove of a plate from each side of the Duo using this technique the plates supplied with the Duo were easily removable.

The good news is that my Pearstone plates are the same plate as the Watson plates. They fit perfectly on the Duo, and mount and dismount easily.

I really like the features on this charger; the voltage/capacity display, the USB power/charging output, the car adapter input and being able to charge a different type and/or voltage batteries at the same time on this charger.

Highly recommended this Watson Duo for its simplicity, quality and features. I always look for great value over the long-run, and this charger overwhelmingly fits the bill. Thanks, AGAIN, B&H!

I have several chargers, but this one is the one that I like and use the most, since obtaining it. I like being able to see the status of the charge and it charges both batteries, simultaneously, unlike the other 2 port chargers that I have. That it comes with a car charging cord is a bonus. It's a keeper for me. No cons that I've encountered to date.

Fits the Nikon EN-EL3e batteries. Need to push down when sliding onto contacts.  Charging is not too slow.  Shows progress and will test battery charge levels.  Does take up horizontal space and is not designed to hang on wall. AC cord is about 53 long. Comes with a 12v car plug too. Has a USB output (not tested). 

Battery plates can be changed to accept other batteries.

I use this to charge Nikon batteries for a Marshall 7 HD monitor on location. It's fast, gives accurate information about % of charge and milliamps--very impressive for the money. I never leave for a location shoot without it!!!

I am based in Bangkok and spent a lot of time wandering around looking for a two battery charger only to be told that none existed. Now back in the USA, I checked B&H and selected the Watson. It works like a charm. Three hours and my truly dead batteries were fully charged. The digital readout is very helpful but most of all, it is great value for the money and includes a car charger as well as a plug in the wall charger. I recommend this product to all who need to charge two batteries and does not want to go one at a time.