The Summer Infant All in One Sheet & Mattress Protector sheet has a top layer that wicks moisture away from baby with its super-absorbent inner layer.  This helps your little one stay comfortable and dry allowing a good nights sleep as well as aiding temperature regulation on warmer nights. The bottom layer is completely waterproof and protects sheets from any damage caused by spills as well as being both soft and comfortable for your baby to lay on. To make life easier the Summer Infant All in One Sheet & Mattress Protector sheet can also be machine washed and tumble dried allowing for easy day to day use.