Two are unused. I'm selling them because I accidentally bought the wrong ones. Built-in type water purifier cartridges, high-performance filter with 17+2 removal effects. - Model name: TJS-TC-S19 - Quantity: 2 - Type: Built-in type - Filter function: 17+2 removal effects I opened one by mistake, so there are 2 left. The remaining two are unused. When sending, I may take them out of the box to fit in the mailbox. Thank you for looking.