3.5-inch floppy disk

A 3.5-inch floppy disk is a small, portable storage medium used primarily in the 1980s and 1990s to save and transfer digital data. It consists of a square plastic case enclosing a magnetic disk that can be read and written to by a computer's floppy drive. With a capacity typically ranging from 720 KB to 1.44 MB, it stored documents, software, and other files, but its popularity declined with the advent of USB drives and cloud storage. The name "3.5-inch" refers to the diameter of the magnetic disk inside the protective casing.