Doesn't last as long as the original(not to far either) but still very good value for the money. I would recommend

Very light and compact. Not the fastest charger, but benefits from charging two batteries at once.

I charged the batteries 1 month ago
When first used, they showed 99%.
So no discharge in the meantime.
During a photo shoot with -1 degrees they withstood the shock well.
4 batteries for about 700 photos. (2 Sony+2 in the kit)
I did not check the difference in discharge according to the brands but with respect to my use it is really a good choice.

Now to see in time.

November 2, 2020
After one year and a few months of use, the batteries work well, up to 30% of battery life remaining, then they are empty all at once, so be careful because over time they lose their discharging powers.
I also noticed that it took longer to charge.
While my 2 Sony batteries have no problems currently.
So I will go ahead and buy two Sony batteries and keep my 2 batteries as backup

October 2021

Well that's it they no longer hold a charge
Drain quickly and go to 0 to 30%
I will keep the charger which is practical and recommend a Sony battery.
They did the job anyway but my Sonys are still top notch.

Really good replacement for the original sony batteries for Sony a series cameras. I tested them and they are even better than the original ones. They lasted longar than the original ones and oh how I love the slim double charger, AMAZING!
I reccomend totally worth it!

I tested 5 under battery brands to replace the original battery for my a6400 (video available on YT).
This battery being 3-4 times cheaper than a Sony, offers a very light better battery life (sony 1h25 in 4K approximately, K&F Concept 1h32) and in addition offers you almost non-existent discharge against the Sony that loses a lot of storage (sony in storage a few months, remains 30% battery, K&F Concept 99%, and it is confirmed in time of recording in 4k, amazing..).
Until then, she beats flat with stitching the Sony...
... BUT (it needed one)...
... she has a small flaw that does not (as much) the Sony. The calculation of the% remaining on the K&F Concept is far from predicted, when the battery indicates 0% it actually remains more than 25min of recording, so you have to get used to keep recording but at 0% and evaluate about 20 min before changing the battery.
Apart from in certain specific cases, it is very uncomfortable but a shame...
(This is the same for the Sony at 0% there are still several minutes of recording.. 10 minutes of head but there is less to spoil if we change to 0%)

In the end excellent battery I use without problems for several months, I strongly advise this battery even faced with the shamefully expensive Sony and that does not hold the charge on time!

Even if I choose, I prefer to get used to calculating that I have 20 good minutes left at 0% (the K&F Concept), than to take out my device after a few months to realize that I have only 10% left (the Sony). (especially 4 times cheaper)

If this comment helped you, do not forget to click on “useful”, thank you.

Small, lightweight, fast and takes a standard Micro USB connector? What's not to like.

The batteries themselves seem very good. They’re a slightly higher capacity that the original Sony ones at 1100mah. Having tested them, they last roughly the same length of time as the original Sony ones which is great.

The charger is small, light, takes two batteries (which charge simultaneously) and takes a standard Micro USB charger (which I’m sure you already have a small collection of). There are two LED lights that indicate when charging and when complete etc. The batteries are easy to load and are actually quite secure when in position.

Overall for the money it’s great and I’m happy to recommend it to any Sony shooter.

Small compact does its job.

The only good thing is the charger. They batteries last for 30 min to an hour maximum.

It does its job

I have several K&F Concept photographic accessories that, with a few isolated exceptions, stands out for offering very good quality products, at generally very low prices.
This is also the case with the set covered by this review, which consists of two batteries and the relative charger.

The two cells declare a capacity of 1100 mAh each, i.e. essentially in line with those of the Sony originals. Actually, in concrete use with both Sony Alpha 7R II and Alpha 6100, the autonomy is very similar to that offered by the standard batteries.
I did not find any sudden power drops, but the behavior during the download is progressive, as is the case with those branded Sony.
Note that the cameras mentioned also show the percentage of battery with these K&F Concept compatible ones, which are therefore recognized as if they were original parts.
The build quality is more than good, without detectable defects.
I would say that these K&F Concept batteries are equivalent to the best compatible batteries, which as far as I'm concerned are the Patona branded batteries, which I have been using for years.

The charger has two separate channels, which is why you can also charge one cell independently of the other.
Each channel delivers 730 mA of current, which means that a fully low battery will be recharged in approximately 1 hour and 30 minutes.
The fact that it is possible to power the charger itself even with a power bank and in general with any USB outlet that provides at least 2.1 A.
This particular model of charger it is more cumbersome than the other K&F Concept brand equivalents dedicated to the same type of batteries. This is due to the fact that the batteries should be inserted in it lying and not strung from above, resulting in an increase in the total volume.

With regard to the price, for 32.99 Euro it is already an excellent purchase.
In my case, I was lucky enough to buy it as 'used as new' for only 15 Euros, including Prime shipping (although the product was sold by a third party seller). I was given a product that has only the words used, because in substance it is indistinguishable from the new factory (perhaps it could be a reconditioned product, perhaps through the mere replacement of a faulty battery).
Given the excellent performance of the batteries and the useful two-channel charger, this is a very satisfying purchase.