100% waterproof: high-tech sewing technology is adopted, with a total of 4 layers of materials. The outermost layer is made of super soft cotton fabric, which is fluffy and soft, giving you a comfortable cloud touch. The second and third layer are superfine fibre filled and waterproof layer:TPU membrane material. The inner layer is made of anti-slip fabric. https://www.sleepycare.com/water...rproof-mattress-top.html