Your students can build over 18 basic models, plus hundreds of variations with this popular model set. The large (13.4" to 3" dia), colorful polystyrene foam pieces can be assembled and reassembled to accurately depict s, p and d orbitals, hybrid orbitals and orbital models of chemical compounds. Central spheres and coordinate rods are all made of wood. Vinyl receptors make connections a snap. Painted with durable enamel, the bright red and green pieces help students distinguish positive and negative orbitals. Each set contains: one s orbital, six p orbitals, 59 orbital lobes, three sigma bonds, six pi bonds, one d orbital ring, 17 central spheres (linear, tetrahedral, trigonal bipyramid, octahedral and planar), plus 22 coordinate rods, 12 coordinate spheres and 19 display stands.a total of 146 pieces. Assembled models measure about 8" high. Furnished with complete instructions.