The AGE Device is a memory system and the power source for the AGE System . It was given to Flit Asuno from his mother before she died from the UE attack on his colony. It is the Asuno family heirloom. Using data from it Flit uses it to build the "Gundam".
In the manga series of Mobile Suit Gundam AGE: Treasure Star, Daiki has a replica of the AGE Device created by his father. It also has the same purpose as the original.
The AGE Device has been the Asuno Family heirloom for many Generations. When it was passed on to Flit he made the Gundam which he used to fight against Vagan in 115 A.G. In 140 A.G, AGE Device were passed into Asemu Asuno's hand on his 17th birthday.
However, in 151 A.G, Asemu were listed MIA after his mission with AGE Device were found during the search, the device was passed into his son, Kio Asuno in 164 A.G.