Sport-Thieme Foam Building Block Wheel: For Sports and Play. The Sport-Thieme Foam Building Block Wheel can be excellently combined with existing large building blocks, such as the U-element. Children can let their creativity run wild and construct imaginative structures or play and movement courses. The building element consists of a solid foam core covered with durable, washable artificial leather. Product details: Core material: Made from high-quality foam block with a density of 25 kg/m3 and a compression hardness of 5.0 kPa. Cover material: Made from particularly durable, washable artificial leather (100% polyvinyl chloride). Dimensions: Ø 120x30 cm, inner Ø 60 cm.