Happy Heiny's only uses custom milled fleece for our diapers. There are no leg casings, which make better fitting diapers and contain messes betterwithout leaving red marks on your baby’s legs.Should the fleece roll out? They are designed so the only thing that touches your child's delicate skin is the soft fleece. Happy Heinys® are available in a variety of solid colors and fun prints. Happy Heinys® solids have been tested for 12 hours or more at night with absolutely no wicking for most babies. The solids have a 100% poly laminated outer layer and will work better overnight. Happy Heinys® Prints have a laminated 100% cotton outer layer and work best for daytime use.