The Salt Water Fuel Cell Giant Arachnoid Kit gives children a chance to learn about new forms of clean energy, while building and powering their very own toy: Feed it saltwater and watch it scurry away...After activating the fuel cell module with a saltwater mixture, the magnesium metal sheet (3 sheets included) can operate the Spider for about 5-7 hours continuously. Because of these life-like similarities, the user may want to stop this insectoid. It is easy, simply take out the fuel cell module and rinse with tap water and dry.