ER-1
this series of exploratory probe droids was produced by the combined efforts of the Naboo and the Gungans, shortly after the Battle of Naboo and the destruction of the Trade Federation's blockade of Naboo. The ER-1 series was created to explore and map the unusual core of Naboo, under the guidance of Graf Zapalo. The lead developers were a husband-and-wife team who had been recruited from Serv-O-Droid, and who retired to their homeworld after the ER-1 was complete. It was a combination of sensitive sensors and components, much the N-1 starfighter, and was hand-built by Zapalo's engineers. They built four droids for their efforts: ER-1A, ER-1B,and ER-1D were used to explore Naboo's core, while ER-1C was deployed to explore the moons of Naboo. The spherical ER-1 can split into two halves on command. The upper half contains a small repulsordrive, and can float over land. The lower half has a specialized engine and housing which allows it to operate underwater.