The Otto Expansion Builder Kit includes all the 3D printed plastic parts enabling interaction an Otto robot. Just open the box and start building right away. Designed to expand the robot's capabilities, this Expansion kit works with the Starter kit (sold separately). Providing the opportunity to add tactile reactions through a series of input modules that allow for a myriad of playful activities. Robots can be turned into an interactive friend that responds to its environment and promotes STEM+ A learning.