This design filled a similar role to that of the advanced droid bomber and while it was more heavily armored, it could carry only a similary-sized payload and its maximum speed was slower. It is only known to have been used during the Invasion of the planet Naboo. 
E-STAP Advanced Droid StarbomberEdit
The E-STAP Advanced Droid Starbomber was a model of automated bomber fielded by the Trade Federation. It evolved from the earlier E-STAP Shielded Droid Starbomber.
Like earlier E-STAP designs, its intended role was similar to that of the advanced droid bomber, which appears to have been used more widely by the Federation. 
E-STAP Shielded Droid StarbomberEdit
The E-STAP Shielded Droid Starbomber was a model of automated bomber employed by the Trade Federation and equipped with a deflector shield generator. It was thus an improvement upon the original, unshielded E-STAP Droid Starbomber, though it is not known to have been fielded by the Federation on many occasions.
It was superseded by the E-STAP Advanced Droid Starbomber.