This type of Disc has a fixed layer break whereas DVD+R DL discs have a break point that can calculated and changed. (thanks to arniebear)
Verbatim DVD-R DL (stats as stated on disc cover)
8.5 GB
215 min
Dual Layer
Warning: Don't attempt to put a Dual Layer (DL) disc into a non-DVD-R DL recorder. It can (and most probably will) result in damage to media/data. Check your DVD Drives' manifacturers site to see what you've got.