Grimm's 60 classic multi-coloured geometrical blocks come in a 3 different thicknesses 1 cm, 2 cm and 4 cm thickness. From easy to challenging, these building block sets are a constant companion throughout childhood! Packaged in natural coloured net bag. Made using European-sourced FSC-certified wood. Grimm's colours are non-toxic, water-based stains that are absolutely harmless and tested in-depth for colour fastness in contact with saliva. This test uses a liquid comparable to standard human saliva. However, some people’s saliva do vary from the “standard”, so some colour may transfer under those conditions, but the stains are harmless.