The 5.25-inch floppy disk is a type of removable storage medium that was widely used in the late 1970s through the 1980s. It is a thin, flexible disk encased in a square plastic shell, measuring 5.25 inches across. This disk could store data ranging from 120 kilobytes to 1.2 megabytes, depending on the format used. Floppy disks were commonly used to transfer files between computers and to store software. They were eventually replaced by more advanced storage solutions, such as 3.5-inch floppy disks, CDs, and USB flash drives, due to their limited storage capacity and durability.