5.25-inch external drive bays can hold several different types of hardware. A DVD burner, like the one shown above, is just one example. DVD burners are similar to CD burners except they can store much more information. DVD stands for Digital Versatile, (or Video), Disk. DVD(+/-)R Double Layer discs burn at two depths on one side of a disc. They are capable of storing up to 8.5 GBs of information. A Double Sided Dual Layered DVD disk burns at two depths on both sides of the disk. It is capable of storing up to 17 GBs of information. CD-R/RW disks can only store up to 700 MBs of information. DVD+R and DVD-R are two different formats for write-once DVD disks. DVD+RW and DVD-RW are two different formats for re-writable DVD disks. RW disks can be erased and re-recorded to, while R disks cannot. DVD-RAM disks are more like removable hard disks. They are not compatible with most DVD-ROM or DVD players. DVD-ROMs have a lower data transfer speed rating compared to CD-ROMs, but 1x for a DVD player is equal to around 9x for a CD player. 6x x 9x = 54x, which means a 6x DVD player's data transfer speed would be equivalent to a 54x CD-ROM.