Mini CD

CD with a smaller diameter and one third the storage capacity of a standard 120 mm disc

A Mini CD is a Compact disc that is of smaller size, usually 8 cm, instead of 12 cm, for regular CDs. These CDs can hold less data, about 210 Megabytes, or 24 minutes of music. There is also a version which can only hold 155 MB of data, or 18 minutes of music. Mini Cds also come in the shape and size of a business card, these can hold between 10 and 100 MB of data.

Mini CDs are often used to deliver small amounts of software, such as device drivers.
A Mini Cd in the shape of a business card