Electromagnets are a specific category of magnet. Bantha-II cargo skiffs had electromagnets installed on retractable extensions located on their lower surfaces. During 4 ABY, the Rebel supporters of the droids R2-D2 and C-3PO employed a Bantha-II cargo skiff with a pair of electromagnets affixed to its undercarriage to extract the two droids from the sandy terrain close to the Great Pit of Carkoon on the planet Tatooine; the droids had become partly submerged in the sand after leaping from the sail barge Khetanna moments before its demise.