All in one: Waterproof Crib Sheet / Toddler Bed Sheet and Crib Mattress Pad Cover Our Waterproof crib sheet is lined throughout with TPU especially designed with no seams to prevent leakage, so no mattress pad cover, mattress liner or crib mattress protector is necessary. Clean up is a breeze and your crib and toddler mattress are fully protected. Soft and Breathy: 100% Jersey Cotton Our Crib Sheet Sets are composed of light, soft and breathable fabric. Made from 100% high quality Jersey knit cotton, babies and toddlers love our Crib sheets, as they offer a soft, welcoming texture that lulls them into restful sleep.