Math Laboratory Model Alpha Chem is manufactures,exporter & suppliers of Math Laboratory Models. Model for Inverse Ratio (Metal) Geometrical Shapes 15x30cms (Coloured) (Set of 12) Stop Watch Pendulum Set (Metal) Volume Relationship Set (Crystal Plastic) Transparent Geometrical Shapes (Set of 10) Conic Section (Set of 4) (Wooden) Meter Scale-Wooden