How does Armor Bane work?

Armor Bane says that it can be neutralized by shields, but does this mean that if the enemy has shields up, it doesn’t do anything, or that it’s just like any other energy weapon and it damages the shields before damaging armor?

As far as we were able to tell early on it meant they did nothing at all

All I know is that the Ripchee beams erase ships. I don’t remember seeing shield graphics on the pirates before they exploded.