... magnet ball you can create infinite number of shapes and patterns. Maybe the shapes you spend your entire life ... a educational tool to help us understand Geometry, Math, and Physics principles.And we can offer kinds of colour: GOLD, SILIVER, ... 3mm,4mm,4.7mm,5mm,6mm,7mm,8mm ,10mm,and so on. If you need other size,pls tell ... us.And we can offer kinds of packing: opp bag , ...