Butt of the Rifle

The  is a non-elemental module introduced in the 16.2.0 update.

Appearance
It appears to be a shoulder stock that is usually found at the end of assault rifles.

Use
It is used to insert in a Primary weapon so that it can be part of a module combination.

Combination
The combination in which this module can be used in is the Turbo Charger. The Turbo Charger, which also requires the Primary Kinetic Module and the Upgraded Magazine, decreases a primary weapon's dispersion and allows shooting without spending ammunition.