A standard automobile radio body size. A DIN radio (single DIN) measures 2x7", while a double DIN measures 4x7". When factory radio/CD players are replaced with aftermarket units, the DIN standard ensures compatibility; however, new or altered dashboard trim may be required. See DIN
and DIN connector
Double DIN Head Units
The double DIN navigation and entertainment unit on the left replaced the stock radio and CD player on the right.