TZ-K2 Replacement Filter for ToLife Air Purifier Filter, Ture H13 HEPA TZ K2 A Air Purifer Filter, 2 Pack

as usual, there's not any kind of filter out there for anything that's reasonably priced for what it really is and how much it cost to manufacture it. having said that, these fit well, the price was reasonable, they came on time, they seem to work just fine. I never had a filter timer alarm sound. But having had the filter in for about 7 months, it was time to change it. I think the timer resets on the filter life meter when you unplug the unit. I was never able to get the unit to reset the timer because it had never been set. But general rule every 6 months or 6,000 hours which is a very odd number of hours. It's about 8 months I believe. My purifier filter is in the kitchen so it needs to be changed more often than if it was elsewhere in the house. But do make sure you wipe down the casing and the inside as well as pop the tab off the side of the unit where all the little holes are horizontally where the micron meter is located and make sure you have that cleaned off. oddly, the unit ran at a high low green status for the first couple of hours after changing the filter. It wasn't a huge difference but mine normally stays around a reading of 08. And it was staying steadily around 20 the first 2 hours after changing the filter. not sure what that was about. But there was no smell on the filter or the plastic in the package.