The Sniper Droideka, also known more commonly simply as the Sniper droid, was a variant of Droideka used for long range combat. They appeared to be nearly identical to the standard Droideka, however had different head designs. They were not equipped with shield generators, but could enter a similar defensive state.
Droideka snipers were armed with long ranged blasters attached to their heads. These blasters could fire at a very fast rate over long distances and posed as a threat to even Jedi when in a good defensive position; their weapon was unable to pierce their own armor, preventing Jedi from destroying them by deflecting back their shots. Although not armed with shield generators, these Droideka Snipers could also enter a defensive position in which they lowered the top section of their head to use as a body shield. It was otherwise only used as a protective plate for the droids when in their rolling positions.
Droideka snipers were seen on the roofs near the last bomb site during the Republic's mission to Kiros. While Anakin Skywalker and Ahsoka Tano were attempting to deactivate the final two bombs, two Droideka snipers appeared on a nearby roof and opened fire on the Jedi. Although the droids gave them some trouble at first, Anakin and Ahsoka were eventually able to find their weak points and defeated them.