During its military reconstruction following the One Year War, the Earth Federation Forces decided to build a high-performance variant of its standard-model RGM-79C GM Kai for use by highly skilled and ace pilots. This new variant, partly based on the GM Kai and the RX-78NT-1 Gundam "Alex" from the One Year War, was called the RGM-79N GM Custom. The GM Custom was equipped with a great number of vernier thrusters, giving it a maneuverability and response time almost equivalent to that of the original RX-78-2 Gundam prototype. It also carried a high-output generator, enabling it to use beam rifles. Due to its high cost, however, only a limited number of GM Customs were actually built. Three GM Customs were stationed aboard the assault carrier Albion during its pursuit of the stolen RX-78GP02A Gundam "Physalis" and in the subsequent battles against the Delaz Fleet.