The V2 series was a less well-known battle droid used during the Clone Wars. It was highly effective and many survived and often found themselves in use by private mercenary groups after the war. They cost 10755 credits new and were highly restricted.
The V2 was designed to be used in surgical strikes and was not generally deployed as a front-line combatant. They often worked in small four unit groups and were very adept at using explosives to accomplish their mission. Some were modified to use their explosive expertise in bomb disposal. They could also be used as an EVA shipjacker.