The EF76 Nebulon-B Escort Frigate was a capital ship manufactured by Kuat Drive Yards. It was used by the Rebellion against the Galactic Empire. These ships are some of the most effective and defensive cruisers in the Rebellion, being able to hold its own against a Star Destroyer. Later on in the conflict, several were refitted with advanced hospital facilities and served as medical frigates.
Five of these were known to show up when Mon Mothma relayed her message to the galaxy, along with several other ships, in the episode, Secret Cargo.