One thing I have noticed. The dust-tight surface is at our bed actually only up to the edges of the soft-side border, everything then goes straight down (on the soft-side surround) is a normal substance. If you put on the mattress, the Slipcover attracts logically inward so that the edge is no more protection is given. This could possibly be the possibility that accumulated dandruff and dust but then fall into the crevice between the mattress and soft-side boundary. Therefore, a star less, but otherwise a really good investment!