I have purchased in this product on Idea 2017 after that I used it for 1 year but I think this is a value for money product
build quality is pretty good but the charging time is the higher side it will take more than 4 hours to charge your 4000 mah battery
And it will take 6 tov7 hours to fully charged
On a single charge I can able to charge my 4000 MH battery which is present on my redmi 3S is 3.4 time is equals to 10600 mah from a 15000 mah power Bank
Which is about 70% of its capacity
When MI power banks are giving 13000 mah
Which is 87% of its capacity
And the charging time is too
My suggestion is if you can charge it for whole night and you have no issue with the charging time it offered and you have money problem then go for it otherwise please buy MI Power Banks
