Each bit has a simple, unique function (light, sound, sensors, etc), and modules snap to make larger circuits. With a growing number of available modules, littleBits aims to put the power of engineers in the hands of artists, makers and children. Contents: coin battery (rechargeable via micro usb cable) bargraph pressure sensor. Snap and play: magnets prevent kids from putting things the wrong way. Play with light, sound, sensing and buttons without wiring, soldering or programming. Kids can make their own interactive objects, or combine with other construction toys.