The Shredder Gun is a heavy weapon in XCOM 2. Like all heavy weapons, it can only be mounted on heavy armor.
|“||This wrist-mounted slug thrower sprays a cone of razor-sharp particles, damaging multiple enemies and shredding their armor.||”|
Fire Shredder Gun: Fire your Shredder Gun in a cone-shaped area.
–Inventory description, XCOM 2