Tweaking ship internals allows you to make a battle cruiser, passenger frigate, or any number of single- or multi-role designs for your ship. 


Core Internals are always present on all ships: Thrusters, Power Plants, Fuel tank etc.
While you must always have one of each, you can vary the makeup greatly to adjust for ships’ characteristics and your build


Optional internals cover Shields together with a myriad of options to adjust your ships defence, performance and capabilities. 
Adjusting Optional internals allows you to accomplish multiple activities with the same ship.


Varying the internals of your ship allows you to create Builds designed to accomplish various tasks – Taxi, Fighter, Explorer – with as many multi-role capabilities as you wish.
Combine Utility mounts and Internals to increase your adaptability.