20000mAh Solar Power Bank Waterproof Emergency Solar Charger 4 USB Ports External Charger Power Bank for Cell Phone by DFITO,Black

Packaging is cheap but product is pretty durable. Don't believe it is 40000mah because it does not say anywhere on the box or product. i have a 16000mah that last the same amount of time, a 17 area heated jacket last 2.5 hrs on high not bad. If on sale is a great deal all ports and plugs that charge items can also charge battery pack. Solar panel is nice if needed. 4 stars because 40000mah i don't believe and no documentation just box and battery.

Purchased originally when we had an ice storm headed our way. We wanted to make sure we had a way to keep our phones charged. I have mixed reviews about this. I give it a 5 stars, out of 5 stars for charging up your phone batteries when you use a regular plug in cable and it plugged into an outlet as you normally charge up your phone, or a backup power bank. It fully charged up I was able to charge my phone and my husbands phone completely once, for the two phones. The next morning I placed the depleted power bank out on our porch with the solar panel up and it flat, and in bright sun for 6 hours and brought it inside, and let it sit as it was warm to the touch because it was 88°F. Later in evening I tried using it to charge and it worked to charge up my husband's phone from 13% to 19% and it kicked off, and I set it put first thing this morning at 6:45, and brought it in a 2:00 pm, and it will kick on for a short minute or two and then kick off again.