A2R disk image
From Just Solve the File Format Problem
The A2R disk image format is a low-level, high-resolution capture of the contents of an Apple II disk. As such, it is much larger in size than other formats such as the WOZ disk image format which attempt to duplicate the data that was originally written to the disk; A2R captures the raw magnetic patterns of the disk, often easier to do in the case of old, barely readable disks, but needing further processing to recover the original data.
