Composite Internal Structure

The Federated Suns introduced the Composite Internal Structure in 3061. Inspired by the Endo Steel chassis, the FedSuns engineers produced a chassis that was light weight but wasn't as bulky as the Endo Steel skeleton. Though they were successful, the materials used in the Composite Structure were incredibly fragile.

Because of the similar name, it is very common to confuse this with the Endo-Composite Structure.

Game Rules
Composite Internal Structure weighs half as much as a standard skeleton, same as Endo Steel, but takes up no extra Critical Slots.

Any damage to a Composite Internal Structure is twice as damaging as that of an Endo Steel or even a standard BattleMech skeleton.

Though the Composite Structure remains an Experimental Technology and restricted to BattleMechs and their subtypes, several combat units have taken advantage of its combination of light weight and lack of bulk to add additional weapons and equipment. For example, it can be used to great effect on Land Air 'Mechs, which are prohibited from using Endo Steel.