I dropped the one I use all the time and the screen cracked.
When I went to an Apple dealer for advice, I was at a loss as I was quoted that it would cost so much to buy a new one even with a cracked screen, when someone told me about Back Market.
I was told that all the products were refurbished.
All have a one-year warranty.
The A, B and C rankings are easy to understand.
I ordered the exact same product, rank B, for 13,800 yen.
I received a proper delivery notice by email and it arrived in two or three days.
Although it was a B rank, I didn't find any scratches and the battery capacity was more than what I was using, so I was very satisfied with the product.
I also use an iPad mini4, but I think I will buy it here next time.