Build and run a race car - just add water! This small but powerful car teaches kids about alternative energy in a fun way. Once built, the car runs on one drop of salt water. Just activate the fuel cell module with salt water and watch the car go for up to 5 hours. No heat is produced, so it's completely safe for kids. The kit includes everything needed to build and run this race car.For ages 8 and up. Build and run a race car - just add water! Runs on one drop of salt water Teaches kids about alternative energy For ages 8 and upSize3"L.