The Elecrian snipers were the soldiers of the planet Elecria, that served as security officers prior to the Battle for Elecria, but joined the Elecrian revolutionaries under the command of Yazil Sayakaz.
The Senb'An'Tiin Confederacy banned any military production on Elecria, so the CIS sent all necessary equipment and weapons to the revolutionaries. Trade Federation as well as Prolla sent their battle droids to aid the Elecrians fight against the Republic.
The Elecrian snipers were primarily used during the Battle for Elecria, but they still could be found later on various worlds helping the CIS armies deal with the clone troopers. They were no longer after 19 BBY, for all leaders of the separatist movement were killed.
Weaponry and equipment
The Elecrians did not have any weapons of their own production, so the Elecrian snipers were armed with E-5s sniper rifle just like the Trade Federation battle droids. In a way the Elecrian snipers could be called the competitors of the Battle droid assassins. Later the Elecrians were using a different model of a sniper rifle developed by an unknown producer.