Knight's Battle Lightsaber

Knight's Battle Lightsaber is premium main hand or offhand lightsaber. It can be obtained by Jedi Knights as a mission reward for completion of the level 26 mission The Sand Demon's Lair, on the planet Tatooine.

Source
Knight's Battle Lightsaber is a mission reward obtained by completing The Sand Demon's Lair, a level 26 mission obtained on the planet Tatooine.
 * Mission reward