baby mattress: 1.Good air&water permeability 2.Washable&drying fast 3.long life and recycle 4.Formaldehyde free This new material is popular in Japan, filler use 3D structure of polymer elastic material. This stereo structure designed for the anti-acarid and anti-bacterial specially.It is excellent air permeability, anti dust & acarus, not moldy, easy cleaning and drying, moderate elasticity, ...