Protosaber

Archaic Lightsabers, often known as Protosabers, were the original form of the Lightsaber. This weapon consists of four parts; hand-carved, duranium hilt, the focusing crystal that sits inside the hilt, the power pack that is strapped to the wielder's back or belt and the power cord that runs from the power pack to the hilt.

These weapons were used by many Jedi before the Great Sith War with Exar Kun. It seems that just prior to this war the invention of smaller energy cells enabled the Jedi - and Sith - to build completely self-contained Lightsaber, resulting in the weapons we now see in the majority of the storyline.