Modular Robotics Battery Cubelet 2.0 This Cubelet provides the energy needed to make your robots spin, drive, and squawk The Battery Cubelet provides 30% greater power capacity, so you can play longer than ever before Easily recharges via micro-USB cable (not included) Pre-loaded with the newest Cubelets operating system, Cubelets OS 4 Compatible with OS 4 Cubelets Six, Cubelets Twelve, Cubelets Twenty kits, and individual Cubelets