64DD

The 64DD is a magnetic disk drive peripheral for the Nintendo 64 developed by Nintendo. It was announced in 1995, prior to the Nintendo's 1996 launch, and after numerous delays was released only in Japan on December 1, 1999. The "64" references both the Nintendo 64 and the 64 MB storage capacity of the disks, and "DD" is short for "disk drive" or "dynamic drive".