"What the--? Oh, blast it! Boys! There's another of them Twin Suns droids here! Hurry!"
- Bull, a few moments before he was killed by ST-97

ST-97 "Steel" was a Rogue-class

ROGUE-A01 Battle Droid Droid Old Republic Battle Droid classes

battle droid used by the Twin Suns pirates

Twin Suns Organization Planetary and Sector

on Tatooine

Tatooine Planet

during the Cold War. In 3643 BBY the droid was guarding a mine in the Jundland Chasm, which was taken over by the pirates, where it was destroyed

Reap the Whirlwind Event Cold War (3653BBY - 3642BBY)

by a team of Republic operatives sent by Jundo Martik

Jundo Martik (Twi'lek) Character Minor Characters (TOR)

to reclaim the mine.
ST-97 was armed with two three-barreled cannons which were a standard for his basic model, and his additional weaponry included incenerator, missile launcher and shockwave generator.