Anker 337 Power Bank (PowerCore 26K) Portable Charger, 26800 (Open Box)

Works great. Well built and meets expected charge capacity. I charged a Note 4 from dead to full approximately 6 times (3220 mah x 6 charges = approx. 19,000 mah). This is well within the expected capacity of a 26800 mah battery pack (all batteries experience some loss when transferring energy to another battery. Typical expected output is about 67% of what's listed. 26800 x .67 = approx 18,000 mah. Charging time (for device, not battery pack) is actually pretty fast even though there is no Qualcomm "QuickCharge". I was roughly getting the following results charging from 0%: after 30 mins - 30% after 60 minutes - 60% after 2 hours - 91% Done around 2.5 hours. So it does seem to pump more juice in at the beginning of the charge. It's not going to get you to 80% in 30 minutes but honestly I didn't want that anyway. This is actually something people should take note of - THE FASTER YOU CHARGE YOUR DEVICE, THE LESS YOU GET OUT OF THE BATTERY. So comparably, 2 battery packs with the same mAh, one charging standard speed and 1 charging using a quickcharge feature, you would get more charges not using the quickcharge pack. The faster you pull energy the more gets wasted (a very simplified explaination). As I mainly want this for emergencies and for camping, I did not want the qucik charge feature anyway but I am still pleasantly surprised with the time to charge. I was expecting longer to be honest. Charging the pack itself was actually pretty quick! I saw some reviews saying it took a 12-24+ hours. They must've been using 1 or 2 low power charging block(s). My wife and I both have Note 4's. I used both Samsung charging blocks (Samsung Adaptive Charge - comparable to Qualcomm QC 2.0) and plugged each one into 1 of the inputs on the Anker pack. I do not have the exact time because, honestly, I was expecting it to take longer. I came back to check progress and it was done! The pack was charged from nearly empty to full in some time less than 4 hours. Very acceptable in my opinion. So why am I only giving this 3 stars? I find merchants emailing me to solicit reviews a huge annoyance. We shop a lot on Amazon and almost every time we buy a product not sold directly by Amazon, we get one of these emails basically begging to write a review. Even though I have asked Amazon FOUR SEPARATE TIMES to stop these types of emails and I have been assured each time to not worry that THIS time Amazon got it right and has updated my email preferences. Yet I still receive these. My typical response is to give these products 1 stars. The fact I gave this 3 stars is only because the battery pack is well built and met my expectations. To make it worse, in the email from Anker there is an unsubscribe link. I tried multiple times on 3 different browsers and kept getting the message "error. please try again later." Maybe if I had been able to opt out of Anker's junk mail I would have overlooked the whole thing but being harassed topped with no way to stop the harassment is getting them a lower rating. To be clear, if you purchase this item YOU WILL BE SOLICITED TO LEAVE A REVIEW by Anker. If this sort of thing bugs you like it does me, you may want to reconsider this purchase. *Note, if Anker addresses the inability to unsubscribe I MAY give them back 1 star but I would highly suggest that Anker stops soliciting people for reviews.