Backup Media set Options:

Default options : NOCHECKSUM,NOINIT,NOFORMAT,SKIP

FORMAT: This option used to specify whether to overwrite the media header information. 

The FORMAT clause will create a new media backup set, whereas NOFORMAT will preserve all the information.

INIT: INIT is used to create a new backup set; NOINIT is used for appending the backup to the existing backup set.

The NOINIT parameter is used mostly when you backup the database to a tape device.

SKIP: The skip parameter is used to skip the expiration check on the backup set.

NOREWIND: This parameter is used to keep a tape device open and ready for use

NOUNLOAD: This parameter is used to instruct SQL Server to not unload the tape from the drive upon completion of the backup operation.