Imation Part # 26598 WORM lto-4 data tape cartridge. Brand New factory sealed. this is a WORM tape, Write-Once-Read-Many. Imation LTO Ultrium Generation 4 Tape Cartridges, manufactured with Imation's proprietary Tera Angstrom Technology. delivers outstanding performance and twice the capacity of LTO Generation 3 cartridges. PLEASE NOTE that WORM (Write-Once-Read-Many)tapes can be used for recording ONLY ONE TIME (ONCE), so PLEASE make sure before placing your order that this is the product you need, OPEN cartridges are NOT returnable.