From Macross Compendium

Energy conversion armor. This alien technology obtained from Macross technology (OTM) where surplus engine output was diverted to defense. It is widely used for variable fighters, Destroids, and naval vessels, etc. It requires a large amount of energy for operation and a variable fighter and Destroid do not have that margin of output so it serves a secondary role (Therefore, increased armoring was developed for the variable fighter). However, the airframe's defensive capabilities greatly improved by the introduction of SWAG, which became indispensable equipment on the variable fighter in particular, where the airframe was weakened due to the transformation mechanism. Therefore, SWAG is widely used in many airframes and is continually improved, even in the 2050s.