What is the difference

[Hope Creek ACA System]

What is the difference between an ACA Howler and a ACA Penetrator (any size)? And when did the ACA Howler come into and out of production? Any pictues of a Howler?

[FS T-Bolt]

dont quote me on this, but i think the Howler was similar to an Allertor...the difference from an Allertor was the Howler was chain/belt driven instead of the worm-gear rotation.

[SirenMadness]

The Howler and a Penetrator have different styles of housings among themselves.
Also, I think that the Howler rotates around a giant collar gear, while the Allertor simply rides along a belt and large pulley.