CD-R = CD-Recordable. This media is known as a "write-once" type of disc. In other words, once data has been written to the disc it can not be erased again. You need a CD-R drive to be able to write to this media. Once data is written to the media it can be read back in a standard CD/DVD-ROM drive. CD-R media can also be written to in a CD-RW drive. Verbatim has been the first to release the latest speed recording for CD-R media using 52x write.

CD-RW = CD-ReWritable. A re-writable disc is one where data once written to the disc can be erased and the disc written to over and over. CD-RW media can only be written to in a CD-RW drive.