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Germguardian Flt21cb4 Airfilter, 13.75Ind, 15Inh, 1.3125Inw, Pk4
$22.29
+ $5.99 shippingReplacement carbon pre-filter pack
GermGuardian Filter J Carbon Replacement Filters (4-Pack) FLT21CB4 replacement filter
Filter J Carbon Replacement Filters (4-Pack) (part FLT21CB4) fits GermGuardian AC5900WCA, according to the official GermGuardian product page.
Official GermGuardian fit · checked
Current marketplace listings
GermGuardian FLT21CB4 prices on eBay
1 part-number-matched listing
Sponsored listings whose titles named the exact part number when fetched. They may be genuine or third-party filters, so compare the pack contents, total cost, and seller before ordering. We may earn a commission from qualifying purchases.
Official package: 4 × Carbon pre-filter elements. Source checked 2026-08-29. Marketplace packs can differ.
Listing data provided by eBay and fetched . Prices, shipping, delivery estimates, and seller details can change on eBay.
GermGuardian models that use Filter J Carbon Replacement Filters (4-Pack) FLT21CB4
This filter is listed for one model. Open a model to see its complete list of primary, optional, and specialty filters.
Official package contents
What's in the box
From the linked official GermGuardian product page. Marketplace packs can differ, so compare before you buy.
Filter J Carbon Replacement Filters (4-Pack) FLT21CB4
- 4 × Carbon pre-filter elements Replaceable Official source checked
Before you order
What to check in a FLT21CB4 listing
- The listing names part FLT21CB4. Similar-looking filters are not proof of fit.
- Your purifier is one of the compatible models: GermGuardian AC5900WCA.
- The pack size and pieces included match what you need. Genuine and third-party filters can differ.
- The total price with shipping, seller feedback, and delivery estimate work for you.
Care guidance
Replacement schedule
GermGuardian recommends replacing the activated carbon filter layer every 2 to 3 months depending on use. Package contains 4 carbon replacement filters.
Usage conditions can affect service life. Follow the cited manufacturer guidance for this part.
Free calendar reminder
Never forget a filter change
Enter the date you installed the filter and we'll make a repeating calendar reminder based on the official replacement schedule.
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Compare compatible options
Other GermGuardian filters for these models
These share at least one compatible model but may do a different job, such as a carbon pre-filter or a specialty version. Check each part page before buying.
Filter J
FLT5900
Frequently asked questions
How often should I replace the GermGuardian Filter J Carbon Replacement Filters (4-Pack) (FLT21CB4)?
GermGuardian recommends replacing the activated carbon filter layer every 2 to 3 months depending on use. Package contains 4 carbon replacement filters.
Which GermGuardian models use the Filter J Carbon Replacement Filters (4-Pack) FLT21CB4?
According to the official GermGuardian product page, Filter J Carbon Replacement Filters (4-Pack) (FLT21CB4) fits GermGuardian AC5900WCA. Verify the model label on your unit before ordering.
Do aftermarket FLT21CB4 filters work?
Marketplace listings may be from the manufacturer or a third party. Match the exact part number FLT21CB4, review the listing details, and verify the model label on your unit before buying.
Official compatibility record
Manufacturer source
Official Guardian Technologies product page identifies Filter J carbon replacement filter 4-pack, SKU FLT21CB4, as compatible with model AC5900WCA.
Guardian Technologies GermGuardian FLT21CB4 - Filter J Carbon 4-Pack
Source compatibility checked 2026-08-29. Recheck the listing and your purifier label before ordering.
GermGuardian Filter J Carbon Replacement Filters (4-Pack) FLT21CB4