LEGO lightsaber! The Switch on the bottom turns on LEDs throughout the blade. I modified the LEGO parts in the hilt to contain eight AA batteries (12 volts total). This was one of my all time favorite projects to build. I like STAR WARS and to combine electronics into LEGO was great fun. The LEGO model needed to be durable enough to be carried by several kids on a STAR WARS themed run called Course of the Force. To pull this off I also added two pieces of three mm threaded steel rod from top to bottom. I estimate that the batteries will power the light saber for about 300 hours. After the run, the durability of the blade was tested when Prince and Blanket Jackson (sons of Michael Jackson) got into a lightsaber duel in the LEGO studio. There was only minor damage and Blanket emerged victorious!