Silver and shaped like a waist-high cylinder, the fastbreeder plants constructed new droids by utilizing materials from their surroundings. They accomplished this by sending out thin silver tendrils into their environment, which leeched minerals and channeled them back to the plant. These roots could even tap into local power grids, vastly increasing the speed of production. From there new droids were assembled inside the nest, before being released.
Fastbreeder plants were also capable of producing new plants, but were seemingly limited to creating an additional two.