Darth Vader's Lightsaber

Darth Vader's lightsaber was the personal lightsaber of Darth Vader, a Sith Lord who served as Darth Sidious' last apprentice and supreme military commander of the Galactic Empire. He built the weapon after he lost his previous saber during a skirmish on Cabarria.

The lightsaber would later be used to destroy Obi-Wan Kenobi and cut off the right hand of his son, Luke Skywalker. During their confrontation on the second Death Star, Luke returned the favor, cutting off the right hand of Darth Vader.

Description
The lightsaber was equipped with a dual-phase function, allowing the blade's length to be manually controlled and altered in combat. The weapon featured a black-ridged handgrip, black power cell chamber, beveled emitter shroud, two dual-phase focusing crystals, high-output diatium power cell; and customary power and length adjustment knobs. Darth Vader was constantly fine-tuning and upgrading his lightsaber for maximum blade power and stability

Because of the modifications Vader made to his lightsaber over the years, its exterior also changed, somewhat, in appearance (though its design was mostly based on his first Jedi lightsaber). Vader appeared to have experimented with a rounded emitter shroud similar to his second Jedi weapon. As a Dark Lord of the Sith, Vader would often utilize his lightsaber during confrontations with Jedi, but also against other opponents, even though he sometimes preferred to use the Force to dispatch lesser victims.