Product review (4 stars): Essential Item for the venta airwasher
You need this item if you are using the venta airwasher. This seems to work well.

But you should keep in mind one important thing. This is for 10 time use(3.5oz each time). You should use this every 2 weeks. So if you have one, you can use for 20 weeks(5 months). But this has an expiration date, which is about a year. So if you have only one venta airwasher, you should not buy more than 2 items of this. If you buy 3 items, you can't use 1 item due to the expiration date.

I rated 4 out of 5 because there is no notion about the expiration date.