Compact discs weigh an average of about half an ounce. A cardboard sleeve adds about 1 ounce to the weight. CDs are optical discs used for storing digital information, including music and data.
The CD format was first created in the 1970s to play recordings of sound but later was adapted for storing data. A standard CD is about 4.7 inches in diameter and 0.047 inches thick. CDs can hold approximately 80 minutes of audio or 700 megabytes of data. CDs are vulnerable to damage from being handled and from being exposed to the environment. Scratches often can be repaired through careful polishing with a soft cloth. As of 2014, sales of audio CDs have dropped by nearly half from their peak in 2000 as sales of digital music downloads have increased.