Purr-Lock™ TriShield Replacement Filter
Refresh all three stages in one click and get your first-day air back.
This store is the only authorized source for the genuine Purr-Lock™ TriShield filter. Filters sold on marketplaces or by third-party sellers are not made by us and are not covered by our warranty.
Compatibility
This cartridge fits every Original Cat Purifier unit, all model years. There is one filter size, so no version numbers to check. It does not fit other brands.
Shipping and returns
Shipping in the US is free. We ship your order in 24 hours. Delivery takes 2 to 5 days. Unopened filters can be returned in the first 30 days.
Three stages. One cartridge.
Every refill restores the full Purr-Lock™ TriShield stack — the same three layers your purifier shipped with, at full capacity.
Fur Capture
A fresh outer mesh again pulls in loose fur, litter dust, and larger particles. This is the layer that clogs first — and the reason airflow drops over time.
Freshness Layer
680 g of activated carbon, unsaturated. Carbon fills up with the odor it absorbs — once it is full, litter smell starts coming back. This resets it.
Freedom Filter
New H13 HEPA pleats trap fine dander and the Fel d 1 allergen at 99.97%. A loaded HEPA layer cannot hold more — this is the stage your allergies feel.
The 30-second swap
No tools. No filters to cut or clean. Three steps, and your purifier is new again.
Turn the bottom ring a quarter turn. The old cartridge lifts straight out.
Remove the wrap and seat the new cartridge. It only fits one way, so it cannot go in wrong.
The filter light turns off and the 2-month timer starts again. That is all.
Is your filter due?
If you recognize two or more of these, the cartridge is saturated.
Questions and answers
How often do I replace the filter?
Replace it each 2 months if you have 1 or 2 cats. With 3 or more cats, or a purifier next to the litter box, plan for 6 to 8 weeks. The filter light on the unit tells you when.
Can I wash the filter instead?
No. Water ruins the H13 HEPA pleats and floods the carbon, so a washed filter stops working. You can vacuum the outer mesh gently between changes, but the cartridge is not washable.
Does this fit my model?
Yes. There is one cartridge size for every Original Cat Purifier, all model years. Remove the old one, drop this one in.
Are cheaper third-party filters the same?
They are not. Most copies use a thin carbon sheet instead of 680 g of pellets, and a lower HEPA grade. Airflow and odor control both drop, and a poor fit lets air bypass the core.
What if I do not need it yet?
Filters store fine in the sealed wrap. Keep it in a closet until the light comes on. Unopened filters can also be returned in the first 30 days.
How does Auto-Refresh work?
We ship a fresh filter on your chosen cycle, timed to when the old one expires. Each delivery is discounted with free shipping. You can skip a shipment, change the date, or cancel in one click from your account.
Two months went by and I told myself the air was fine. Changed the filter and by that evening the litter room smelled like nothing again. Now I order two at a time so I stop procrastinating.
Quarter turn on the base, old one out, new one in, hold reset. No tools, nothing to line up. It only goes in one way so you cannot mess it up.
Bought a third-party filter to save ten dollars. Airflow was noticeably weaker and the odor difference was gone within a month. Went back to the real cartridge and the difference was immediate.
No complaints about performance — it is like the purifier is new again. With three cats I get closer to six weeks than two months, so I buy the 3-pack to bring the cost down.
You can see how much carbon is in this one compared to what I pulled out of a different purifier. That is why the odor control actually holds up for months instead of weeks.
I used to forget to reorder and run weeks on a dead filter. Now it just shows up right when the light comes on, and it is cheaper than buying one off. Set it and stopped thinking about it.
Your purifier is only as fresh as its filter.
Keep a refill on the shelf so the air never slips back. Free shipping, and 30-day returns if you change your mind.
Free shipping · Ships in 24 hours · 30-day returns