One size fits all– you can adjust the diaper to your desired size (SM or L) by snapping onto different rows of buttons on the nappy. Hip snaps and crossover snaps to prevent “wing droop”. Washable waterproof and breathable. Materials: 1Inner layer:lycra milk shreds with waterproof and breathable TPU.2Outer layer:Only Lycra milk shreds  caring for babys delicate skinkeep your baby dry. Tips & Care: 1Wash before first use. Please wash colours separately. 2It usually will take a few washes to reach its full absorbency (could be 6 washes or more).