The 64DD is a peripheral developed by Nintendo to expand the capabilities of the Nintendo 64 with rewritable magnetic disks and online connectivity. Announced in 1995 before the Nintendo 64's 1996 launch, it faced multiple delays before its release in Japan on December 11, 1999. The "64" references both the Nintendo 64 console and the 64 MB storage capacity of the disks, while "DD" stands for "disk drive" or "dynamic drive". Despite its innovative features, it struggled to gain traction and was discontinued after a short-lived run in Japan.