Reviewed by 3 customers
I got two. One charged immediately, the other took several attempts before it would take a charge. Both showed a full charge in a short time which makes me think they do not hold much energy. I am sure they will be fine for back up; I have not used either yet.
This battery, bought as back-up for the NX20, does the job, it recharges pretty fast in the Samsung charger, and it'd amazingly cheap, but... It appears to run done fast, and rather suddenly toward the end, taking me by surprise. I'll use it gladly, and can recommend it, but I've ordered two more official Samsung batteries to properly cover myself.
Seemed to work just as well as OEM, but for less.