Hello today I review mi power bank 2i 20000. A few months before I have 2600 mah battery phone which not provide long battery backup for me so I had decided to purchase high capacity power bank. When I look online I found this power bank useful for me than I booked it and use it. Design of this power bank loking dynamic and good .It works really good for me it can take very small time to charge my phone and there were no heating in power bank during charging .it support fast charge ( 3.6 A) . It has low power mode. Power bank takes 7 hrs to full charge.it can charge my phone 4 or 5 time. At the starting it works really good but after 3 or 4 month its efficiency getting down. And after 1 year its has charge my phone only one time after full charge of power bank.