Styropor Polystyrene Hollow Sphere Ball 15cm Hollow polystyrene balls in two halves which slot together. Ideal for floristry or craft projects. 15cm polystyrene balls can be painted and decorated with a multitude of craft and modelling materials, they can also be used as a base for clay modelling, paper mache or plasticine. Oasis styropor spheres are light, waterproof and easy to use. Great for wedding decorations, hanging novelty and table decorations. Use whole or split into halves