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Captain O-Ring - K4 Replacement O-Ring Kit for OmniFilter K4, CBF1, CBF3, SFM2, U30, USM2, OT32, RO2000, RO2050, and More (2 Sets, 8 Orings)

4.6 (8) Write Review
Free shipping on orders over $29.99

$11.59

$ 4 .99 $4.99

In Stock

About this item

  • The Replacement OmniFilter K4 O-Ring Kit (also called K4-4PAK, K4-R, K4-04, K4-DC6-S18) contains 4 different o-ring sizes to fix your leaking water system.
  • This convenient 2 set package contains 2 of each size, for 8 o-ring gasket seals total.
  • Compatible with: OmniFilter CBF1, CBF3 Series A, CBF20, OB3, OB5, OT32 Series A, Omni Super, Omni Deluxe, Omni Regular, OT5, RO2000, ROT2000-TDS, R12, R14, SFM2 Series A, Total 2, Total Plus, UC2, U30, U400, U450, U500, U600, U700; Culligan US-316; DuPont WFDW12009W, WFDW12000, WFDW13000, WFCH1; and Falsken Heater Treater [FAL-OR-KIT / The Heater Treater 10/20 Replacement O-Ring Kit].
  • Molded from NSF 61 certified buna-n rubber for safe and clean drinking water.
  • Manufactured and warrantied by Captain O-Ring LLC. Proudly assembled in the USA!


Product Description

The OmniFilter K4 Replacement O-Ring Kit (also called K4-4PAK, K4-R, K4-04, K4-DC6-S18) contains 4 different o-ring sizes. This convenient 2 set package contains 2 of each size, for 8 o-rings total.

Compatible with:

  • OmniFilter CBF1, CBF3 Series A, CBF20, OB3, OB5, OT32 Series A, Omni Super, Omni Deluxe, Omni Regular, OT5, RO2000, ROT2000-TDS, R12, R14, SFM2 Series A, Total 2, Total Plus, UC2, U30, U400, U450, U500, U600, U700
  • Culligan US-316
  • DuPont WFDW12009W, WFDW12000, WFDW13000, WFCH1
  • Falsken Heater Treater [O-Ring Kit Part Number: FAL-OR-KIT / "The Heater Treater 10/20 Replacement O-Ring Kit", includes both the smaller slimline size and the larger standard size]

What to expect: This item includes eight (8) o-rings (4 sizes, 2 of each size) in a resealable zip-top poly bag with "Captain O-Ring" branded packaging.

Manufactured and warrantied by Captain O-Ring LLC. Proudly assembled in the USA!

Includes four (4) different o-ring sizes. Two (2) of each size. Eight (8) o-rings total.

3.86

3.86" Inside Diameter x 0.14" Thick

3.48

3.48" Inside Diameter x 0.14" Thick

3.36

3.36" Inside Diameter x 0.14" Thick

3.28

3.28" Inside Diameter x 0.10" Thick


P. Souza
2025-07-29 18:00:23
These fit my under cabinet water filter perfectly. No issues.
Bob Lablaw
2025-07-02 10:54:08
I did not realize there were two different sizes in the package. First one I pulled out was too small and I was not happy. Then when I was putting it back in the bag is when I saw the two different sizes. The next one I tried worked perfectly.
Angela L.
2025-05-09 10:10:52
It was a good price but I feel.it should have been included with the order of the filters
nelson king
2025-05-03 15:05:00
Great assortment of o-rings for whole house water filter. Works great.
Eric in Cincinnati
2025-03-25 15:56:55
The 4 options are good, but it did not fit my older filter.... Good news, the seller did allow returns...
Janice Wisinski
2025-02-24 10:56:21
These O-Rings are for my under-the-sink water purifier. The package comes with different sizes to fit many types of filters.
Susan Joseph
2025-02-02 13:35:54
This product didn't work for us. Because it was too thin it didn't stop the leak.
Kent W.
2025-01-01 17:10:21
Should send it back as it is a 2nd rate after market product.....made to look as if it was from Omnifilter.....2 of the o rings won't even work