Two versions of LTO were planned, but only the Ultrium version was released, using ½ inch tape in a single-reel cartridge. The first generation could contain up to 100 GB on a cartridge. The latest generation (version 6) released in 2012 can hold 2.5 TB.
The tape inside an LTO cartridge is wound around a single reel. The end of the tape is attached to a perpendicular leader pin that is used by the drive to grasp the end of the tape and mount it in a take-up reel. When a cartridge is not in a drive, the pin is held in place at the opening of the cartridge with a small spring.
Most manufacturers produced different generations of LTO cartridges in different colours, generally being 1) Black or gray, 2) Purple, 3) Blue-grey, 4) Green, 5) Dark red, 6) Black.
Every LTO cartridge has a memory chip inside it, with a total of 8 KB on newer generations. This is used to identify tapes, identify generations of tape, or store tape-use information.