Engino  Upgrade Set from 30 to 40 Models Expand Engino's inventor set 30 to set 40 without having to buy the bigger set at full cost Multidimensional construction system, Build structures and machines with 114 parts Printed instructions are included with these fun, easy to assemble models - more plans can be downloaded from Engino's website Excellent addition to a home-school curriculum Another fun, educational product from Elenco, the company that brings you Snap Circuits