I bought this for my daughter when she was 2 months old. The mattress that came with her moses basket has a plastic cover front and back. It is not removable. When i picked my daughter up in the morning her back was wet where she had been sweating as her skin couldn't breathe. I bought this mattress in the hope that it would let her skin breathe so she would be more comfortable. It did not dissappoint. Now when i pick her up in the mornings she is bone dry. Not an ounce of sweat so it is clearly doing the job.
Although the cover is not removable it is water reppellant. Day two of having it my daughter threw up an entire bottles worth of milk (7oz) in her moses basket. Though she had been thouroughly burped, there was obviously some she wasnt parting with until the most awkward opportunity! It went on her blanket, sheet, fitted sheets, moses basket liner - both of them! And of course on the mattress. Water repellant it is, it did not soak through to my relief! I sprayed a cloth (rather than the mattress) with a disinfectant spray and wiped over the mattress. I then left it to air for the day in a room with the window ajar just to let it breath. Later that afternoon i went back, it was dry, didnt smell and was ready to be made up again for that night. I was originally disappointed that the cover didn't come off but when challenged by a real baby disaster it did not let me down! Money well spent and peace of mind that my little girl is more comfortable at night.