Type I cartridges are non-removable for both single-sided and double-sided DVD-RAM media.
Type II cartridges are removable for single-sided media.
Type IV cartridges are removable for double-sided media.
Currently,Companies such as Panasonic , Verbatim and Imation offers the following DVD-RAM choices:
a. 5.2-gigabyte (GB) double-sided media in a Type I cartridge
b. 2.6-GB and 4.7-GB single-sided media in a Type II cartridge
c. 9.4-GB double-sided media in a Type I and a Type IV cartridge