A transmission pack was a device that was worn by the modified B1-series battle droid Roger, who served the Freemakers following the Battle of Hoth. The Sith agent Naare planted a tracking device on his transmission pack during a trip to Tatooine. This allowed her to track down the Freemakers and to steal the Kyber Saber crystals from them. After escaping Naboo, the Freemakers discovered that Naare had been tracking them using Roger's transmission pack.
They promptly removed it. Later, Roger reinserted it in order to save the Freemakers and Jek-14 from being killed by the rebellious droid N-3RO and his fellow mutineers. This attracted the attention of Naare and her new ally Graballa. Rowan Freemaker then used the transmission to dare Naare to race him to Hoth, where the last kyber crystal was located.