One genuine part, one third-party listing, and a clear line between who is claiming what.
Core 300-RF is the code on the cartridge, and it is the only reliable way to shop for this part. The machine on your desk may say Core 300, Core 300S, or Core 300-P on the front, and those names have been applied across more than one generation.
Two listings here carry this code and they are not the same kind of claim. One is the genuine Levoit part. The other is a third-party cartridge whose seller states compatibility with the Core 300-P and 300S-P. Both are listed; neither is presented as the other.
Nothing on this page extends a compatibility list by inference. Where the genuine listing names one machine, one machine appears. Where the third-party listing names two, two appear. A cartridge that fits a 300-P is not automatically right for a 400S-P because the numbers look related.
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Genuine
Sold by the company that built the machine. The compatibility statement comes from the party who designed the airflow path.
Code on the cartridge
Levoit Core 300-RF Filter
Core 300-RF is the code printed on the cartridge you are pulling out, and this is the genuine Levoit part carrying it. The listing states it is for the Core 300-P, that it is AHAM Verifide, and that it includes activated carbon. Matching the code beats matching the description of the machine, because Levoit ships several Core models with cartridges that look alike.
What the listing supports, and what it does not
The code on the listing matches the code molded into the cartridge, which is the whole test
Stated as a genuine Levoit filter rather than a compatible one
The listing states AHAM Verifide status
Activated carbon is stated as part of the assembly
The listing names the Core 300-P specifically, so other Core numbers need their own check
Single cartridge, so there is no spare waiting when the indicator comes on
Genuine parts usually cost more than the compatible listings on the same page
Best forA Core 300-P where you would rather not think about whether a filter fits.
Fit is asserted by the seller, not by the appliance manufacturer. Read the named model list against the label on your own machine.
Core 300 Compatible Filter for Levoit Core 300-P and 300S-P
Third-party listing
A third-party cartridge whose listing states compatibility with two Levoit machines, the Core 300-P and Core 300S-P. The compatibility here is the seller speaking, not Levoit. It sits on the Core 300-RF page beside the genuine part so the two claims can be read next to each other, and it is listed under the models the seller names rather than the whole Core 300 family.
What the listing supports, and what it does not
Two Core 300 variants are named individually in the listing
Gives a second option when the genuine part is out of stock
The model names line up with the code on the genuine cartridge
A single part with nothing extra to track
Compatibility is stated by the seller, not by the appliance manufacturer
Fit and material are not verified against the machine maker specification
A compatible cartridge can affect how the machine reports filter life
Best forA Core 300-P or 300S-P where the seller compatibility statement has been read and accepted.
2 entries sit below, drawn from 1 genuine and 1 third-party listing for Core 300-RF. Each one is here because a listing names it, and no numbering pattern has been read as a compatibility claim.
Levoit Core 300-P (stated by the genuine listing)
Levoit Core 300-P and 300S-P (stated by the third-party listing)
How to check your own
Open the filter door and take the old cartridge out — the code is printed or molded on the plastic rim.
Read the code off the cartridge itself rather than the model name on the front of the machine.
Check the sticker inside the filter compartment, where most machines repeat the part number.
Match that code against the listing, and read which machines the listing names before ordering.
When it gets changed
Levoit states a replacement interval for the Core 300 series, and the machine tracks running hours and signals when it thinks the cartridge is due. Rooms with pets, smoke, or nearby construction load a cartridge faster than the stated interval assumes.
To repeat what is said at the top of the page: the Amazon links here are affiliate links and may earn this site a commission. Ordering, badges, and every claim on the page were decided from what the listings state, not from any commercial arrangement.
