This one is a 24000mAh. It comes with the battery, charging cable, instructions and warranty card.
The Battery has an IC chip that makes it give your device the right amount of current to prevent overcharging and overheating. The charger can deliver 2.4 amps but your device will only draw what it requires to charge. It also has a 5V 1A input and DC 5V 2.1A/5V 1A output, so the battery pack itself will charge faster.
The battery has a couple things I like just press the power button on the side to see that it has a 4 LED indicator light in the upper corner to show how much power is remaining in it. It also has an auto off feature that turns it off after 10 seconds. The also has a spot in the corner to attach a lanyard, key ring (kind of big for that) or a clip and then you can clip it to your backpack or belt loop.
Now on to performance. I don’t have a fancy meter or anything. I just use an old galaxy tablet and if it charges it then it passes my test. If it does is more than once then great. It charged it once and now it needs to be recharged again so it passed my little generic test.
Selectec offer a 30% OFF coupon code L84VPHZL for this external battery, which expires on 4/30/2016, just find it on Amazon.