The outer sheets have two small holes from which the air escapes when compressing the cubes. This has the advantage that they give immediately when children throw it. The downside is that they should not use it in the tub / in the water, because it takes forever to get all the water is out again.
Great we find the various, simple motifs and symbols that you can use to explain. The cube smelled only slightly plastic, or are hardly available exhalations. The print is water or suck firmly; nothing flakes.
IMHO they are suitable for babies / children aged 9-18 months.
