Perfect fit for Mi 20000mAh power bank. Protects the device from scratches. May not protect from heavy falls though. 2 sides and the Mi logo portions are still open and may prone to scratches. You might want to affix a cellophane tape over those sides if you want to protect those sides from scratches too. Otherwise its OK.
Slightly expensive according to it's role. It doesn't protect the power bank from accidental falls rather it just protects the surface against scratches. It's not dust proof also. Catches a lot of dust on its surface. But due to unavailability in markets, you can go for it.