Bests & Worsts Reviews from Amazon

WARNING: YOU MUST HAVE A USB-C POWER DELIVERY (PD) CHARGER TO CHARGE THIS DEVICE! AN ADAPTER FOR USB-C TO USB WILL NOT WORK! I left this on overnight (~11 hrs) charging on my Anker wall charger (Quick Charge 3.0 43.5W 4-port USB charger) with a USB-C to USB adapter (because both ends of the supplied cable are USB-C) and it didn't charge it one bit. Had to return it. I felt 3 stars was generous since nowhere in the product description did it say you needed a PD charger, which is not supplied. I'm not about to buy another special charger when the one I have is awesome. UPDATE: On 10/29/19, Anker customer support reached out to me because of my original review asking about the issues I was having. I didn't initially reply due to my schedule but two days later I got another email saying they had sent me out a complimentary power bank (this model) AND their 30W PD charger. I received them about 4 days later and so far have satisfied with the performance. The power bank charges rapidly out of the box with the PD charger (took less than 6 hours from a 50% out-of-the-box charge). It fast charges my Galaxy S8 as well. With 20000 mAh I'm sure it'll be a few days of fully charging my S8 before I ever have to recharge the power bank. I don't like the idea of needing to have a special charger for it, because now that's just one more charger I have to keep track of but it is what it is. Anker products haven't let me down before and I'll remain a customer for a long time.