Hello, I'm looking for a nice and thin leather(imitation) sleeve for my MBA. I don't need extra pockets or such. I've found some but they all have magnetic clasps... So I'm wondering if there is the possibility of damaging my MBA because of these magnets? Also I'm not sure if I should buy a sleeve for just 18/20$ or a better one for 70? Or could someone recommend a leather sleeve for a MBA? Thank you for your help!!