LTO-Ultrium Universal Cleaning Cartridge is compatible with all manufacturers' LTO Ultrium 1 2 3 and 4 drives and provides up to 50 cleanings or as many as your particular drive allows. Cleaning is done by shuffling a specific amount of tape over the drive head based on a specific cleaning algorithm that is unique to each drive manufacturer. Cleaning reduces built-up or stains that get deposited on drive heads and should be done whenever the drive's "use cleaning cartridge" signal is flashing. It is recommended that you keep track of the number of times you use the cartridge and discard it after it reaches the maximum number of uses for your drive model. In addition the cartridge has an RF (radio frequency) LTO-CM (cartridge memory) that keeps track of the number of times your cartridge has been used. Most drives will read the CM see when your drive has been used the maximum number of times and will no longer use that cleaning cartridge.