Archaic lightsabers commonly referred to as protosabers were the first known design of lightsaber. Like later lightsabers, their focusing crystal was set inside a hilt from which a blade of energy was emitted. The main difference between protosabers and later lightsabers was that the hilt was connected via cable to an external power pak due to limitations in power pack technology. These lightsabers had limited power life and the mobility of the user was restricted by the cord linking the hilt of the weapon to the power supply.