A technological component known as a comlink booster pack was typically affixed to the rear of most B1-series battle droids. Its design and purpose varied among different battle droids, with distinctions observed between B1 droid sub-models, the droids' assigned military role and allegiance, and specific droid units.
Within the Geonosis primary droid foundry, B1-series battle droids exhibiting rust-brown plating were outfitted with a comlink booster pack during assembly. This booster pack was a standard piece of equipment for most B1-series droids, attached to the back of their bodies.
The packs' form and appearance differed depending on whether they were used by B1-series droids serving in the Trade Federation Droid Army or the Separatist Droid Army. Trade Federation droids had booster packs with two antennae of varying lengths, which extended when the battle droid was activated by a central computer. In contrast, some Separatist droids' packs only had one antenna. However, Separatist B1-series battle droids present during the First Battle of Geonosis, which were built by the natives of Geonosis, had two antennae of differing length.
Separatist battle droids had their booster packs mounted onto twin rails on their backs. Federation droids' packs featured numerical markings for droid identification. A battle droid without the pack would secure their standard E-5 blaster rifle onto one of two rails on their back. However, a Federation battle droid equipped with a booster pack would place their blaster rifle beside the pack. Separatist droids of the Agamar garrison—who remained on the planet Agamar during the Galactic Civil War after crash-landing on the world during the Clone Wars—stored their blaster rifles at the back of the pack instead.
Separatist battle droids aboard the bridge of a Munificent-class star frigate at the Battle of Quell did not have the antenna extended. Some droids stationed on the bridges of Confederacy Munificent-class frigates commanded by Cad Bane during the Battle of Devaron were completely without booster packs.
Within the OOM-series battle droid line, only select OOM command battle droids were equipped with a booster pack. Certain Separatist OOM command battle droids, such as 224, displayed a yellow, circular marking on their booster pack, although it lacked the numerical markings used to identify the droid. OOM-9, the Trade Federation field commander during the Battle of Naboo against the native Gungan population, did not have a comlink booster pack, even though the OOM command battle droid had the pack's two antennae installed on the back of his torso.
The concept of comlink booster packs originated from Doug Chiang's idea of B1-series battle droids using jetpacks, developed during his work on the 1999 prequel trilogy film, Star Wars: Episode I The Phantom Menace, where the booster packs made their initial appearance.