This product is everything that it is promised to be. It holds it incredible amount of power, and charges multiple devices at once efficiently. It charges devices extremely fast and is good for 5-10 full charges before it needs to be recharged. The only complaint is that it does take a very long time to recharge itself after being drained and Its a little bulky and cumbersome. Otherwise this thing is awesome!
Its a great product.
I have a 20000mah unit and it takes around 20hrs with regular USB and 6hrs using USBC.
Small price to pay for that amount of charge in your backpack.
I have the Anker PowerCore+ 20100 USB-C and love mine. It takes forever to charge, almost 20 hours and about 6 with power delivery as well.
Wonder if you can speed it up a bit, maybe use a stronger/faster charger