Barriss Offee wielding her lightsaber
Barriss Offee's lightsaber consisted of a metallic hilt with a cap on the pommel end and a ringed emitter from which the blue plasma blade would emerge once the weapon was ignited. It also had a number of prominent dials and buttons on it that allowed Offee to control the blade's activation and intensity but without interfering with her combat grip. After Offee began to give into the dark side of the Force, she would instead find herself fighting with Asajj Ventress's red lightsabers, deciding that they suited her.
Offee used her lightsaber during the First Battle of Geonosis. While she tried to stay away from the Clone Wars for a time, Offee found herself returning to the conflict with the Second Battle of Geonosis, during which she wielded her lightsaber. She also wielded her lightsaber in the subsequent skirmish aboard TB-73, where she killed clone trooper Trap by igniting it through his stomach to prevent him from infecting her with a brain worm.
Offee continued to carry her blue lightsaber until her fall to the dark side of the Force in 19 BBY, where she bombed the Jedi Temple and framed her close friend Ahsoka Tano for the deed. When Tano's master, Anakin Skywalker, deduced her involvement, he went to Offee's quarters in the Temple and confronted her, "casually" picking up her lightsaber and examining it whilst asking questions before igniting it and lunging at her with her own weapon. This caused Barriss to instinctively summon Asajj Ventress's lightsabers to her hand to defend herself, exposing herself as a traitor. Skywalker then proceeded to duel her using her saber alongside his own throughout the Temple, the fight carrying on outside to a ledge above the training grounds where Offee knocked Skywalker down towards the ground before leaping down to attack him, knocking her former Jedi lightsaber from his grasp.