Mattresses purchased already know. As my husband and I have two hyper allergic we wanted for our two daughters correct hypoallergenic mattress and this one is. Our greatest advantage of this mattress here with her nanny and no allergic reaction at 18 months from which we use. The case in which it comes also allows power transported without risk of damage (useful when the child part 2 or 3 days with her grandparents (and more comfortable than a small umbrella bed mattress). Good investment