Nothing brings a LEGO® model to life quite like a bit of light and/or sound. Between 1986 and 1998 and there was a 9V system dedicated to this, and made available in a number of Space and Town sets of the era. This system had a battery box (8studs x4studs x2 2/3plates), and had some exposed powered studs that a light brick could be placed on, or a siren brick. It was also the power system for the monorail sets of that era.