Cleansui CSP Series Water Filter Cartridge, 1 piece - Set includes: 3 pieces - Series name: CSP Series - Model number: HGC9SZ - Usage period: 6 months - Filtration capacity: 450L or more Thank you for viewing. I am selling the remaining 1 piece because I can no longer use it after moving. I used 2 pieces, so the box has been opened, but the contents are unopened.