The Drill Mod 3 is a Terrain Tool augment that can be used to dig through harder terrain than the Drill Mod 2 allows.
To use the Drill Mod 3 it needs to be attached to one of the three slots on the Terrain Tool. Use the tool as normal to dig through soil. Use of the drill mod requires power, and it will drain the backpack supply quickly. For longer use connect to tethers or have power generating items in the backpack, such as Small Wind Turbine or Small Generator.
It is the best drill mod to use, allowing the player to be able to dig through any hardness of soil. Exercise caution at base, however. This mod will allow the Terrain Tool to dig through the dark grey soil generated around a deployed Shelter.