LS-120 or SuperDisk is a high-speed, high-capacity alternative to the 90 mm (3.5 in), 1.44 MB floppy disk. It is called High density media. The main advantage when compared to FDD and ZD is the possibility to use the united mechanism for these special diskettes even for FDD and ZD. This SuperDisk was introduced by Iomega in 1995 as ZD. But the SuperDisks were not expanded because of slowness and unreliability in comparison with ZD.