Pictured is the command tower from the Devastator, an Imperial I-class Star Destroyer.
Command towers, sometimes referred to as conning towers, served as external structures housing the bridge on several warships of the Galactic Empire. An example of an Imperial vessel equipped with a conning tower is the Imperial II-class Star Destroyer. Notably, during the Battle of Hoth, a v-150 Planet Defender from the Rebel Alliance's ion cannon struck the conning tower of the Tyrant, an Imperial II-class Star Destroyer, resulting in its destruction. Due to the vulnerability of these exposed conning towers on Imperial warships, the First Order opted to exclude them from the design of their Resurgent-class Star Destroyer.
Imperial-class Star Destroyers' command towers featured either a tractor beam targeting array (on Imperial I-class Star Destroyers) or a communications tower (on Imperial II-class Star Destroyers and modernized Imperial I-classes), accompanied on each side by two deflector shield generator globes.