This Tefal XD9070 Anti-lime cartridges Liberty is a refill for the Tefal Liberty steam generators. You replace an anti-scale cartridge every 3 months. This way you keep the steam generator free of lime and protect your clothing against brown spots. With an anti-lime cartridge you do not need to worry about lime in the iron or brown rust spots on your new shirt. With this package of 2 anti-calcium cartridges you will be able to continue worrying for 6 months.