Eccentric suppressor designs (i.e. offset so the bullet does not go through the middle) have been around for quite a while - and the most popular modern example is definitely the SilencerCo Osprey.

The problem with round suppressors on pistols is that they tend to block the factory sights.  That can be worked around by replacing the sights with either an optic or higher "suppressor" sights; but, eccentric suppressors solve the problem altogether!

With the Illusion, AAC was able to produce the FIRST 9mm pistol suppressor that is truly compatible with factory sights.

On top of that, the Illusion 9 is also FULLY USER SERVICEABLE.