An annual replacement cartridge for both 15 mm and 22 mm BWT Aquadial Combi-Care Scale Reducer kits. The replacement cartridge is easy to change, and assists in treating water before it is heated, helping to prevent limescale from forming and subsequently improving the boilers service life and increasing hot water storage efficiency. Fits both 15 and 22mm Combi-Care Systems. Easy change cartridge. Deep drawn aluminium canister - recyclable. 12 months cartridge life. Fits some other similar systems. Treated water remains potable. All materials BS6920 certified. BWT AC002400 Combi Care Replacement Cartridges, White. Easy change cartridge. WRAS approved product. 12 Month Cartridge Life.