This was the first lightsaber constructed by Luke Skywalker and the second one he owned. The design was based on schematics Luke found in his mentor’s hut on Tatooine.
Luke used his lightsaber during his final confrontation with Darth Vader. When Palpatine was inspecting the lightsaber, he claimed that the design was much like his father’s. At the climax of his duel with Vader, as he stood with the weapon leveled at his fallen father’s throat, Luke refused to give in to Palpatine’s goading to slay his father and submit to the dark side of the Force, shutting his lightsaber off and hurling the weapon aside.
For decades, fans were intrigued by a rumored “lightsaber construction scene” in which Luke constructs this lightsaber in a cave on Tatooine.