Usage: scsi_readcap [-b] [-h] [-l] [-v] <device>+
  where:
    -b, --brief          output brief capacity data
    -h, --help           print usage message
    -l, --long           send longer SCSI READ CAPACITY (16) cdb
    -v, --verbose        more verbose output

Use SCSI READ CAPACITY command to fetch the size of each <device>