The 26120017 is an LTO Ultrium cleaning cartridge. Unlike other cleaning cartridges, LTO cleaning cartridges can only be used a certain number of times (usually 50) before the drive will reject them as used cleaning tapes. This is because the 26120017 and other LTO cleaning cartridges feature a chip which stores a range of information and has an embedded code that is used to identify itself as a cleaning tape to the tape drive. Once the cleaning tape has been used the requisite number of times, it is rejected by the tape drive and only new cleaning cartridges can then be used. This LTO cleaning tape is for use with IBM tape drives.