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iSpring FC15BX4 4.5x10 in. 5 micron Carbon Block (CTO) Water Filter Replacement Cartridge for Under Sink and Whole House Water Filtration Systems, Pack of 4

Regular price $133.99
Sale price $133.99 Regular price $133.99
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iSpring FC15BX4
$133.99

Features

us21b replacement filters
water filter for whole house

Why iSpring?

At iSpring, we look beyond technology to make high-quality drinking water accessible for all households. We provide our customers with professional water solutions to any water concerns you may have.

ispring water filter

Outstanding Performance

The FC15B carbon block filters are made of high-quality coconut shell carbon and are specially designed to remove up to 99% of chlorine from water as well as various other contaminants that cause unpleasant odors and tastes.

whole house replacement water filters

High Capacity x 4

Each FC15B CTO Carbon Block filter has a filtration capacity of up to 50,000 gallons of water. This economical pack of 4 FC15B filters provides a family of four with clean water for up to 2 years.

whole house water filter

Safe Water For the Ones You Love

Save on your water bill - the filters won’t produce any wastewater.

Official 2nd stage filter for iSpring under sink water filter US21B and whole house water filtration system WGB21B; 1st stage for WGB21BM and WGB21B-PB.

Fits standard 10” x 4.5” filter housings.

Unlike an RO membrane, the CTO filters don’t reduce Total Dissolved Solids (TDS). They keep healthy minerals in your water instead. If you are interested in a filter that removes TDS, consider our iSpring Reverse Osmosis (RO) systems such as RCC7 series and tankless RO systems like RO500.

  • AvailabilityIn Stock
  • Model FC15BX4
  • Manufacturer iSpring
  • Product Weight 4.0 LB

iSpring vs Other Brands

Feature
NSF/ANSI 58 Certification
Yes (full system certified)
Often partial or none
Verified performance & safety
Filtration Stages
Clear 3/4/5/7 stage options
Usually 4-5 stages
More complete options
Alkaline Remineralization
Available (RCC7AK/RCC7AK-UV)
Rare or expensive add-on
Better taste & pH balance
See-through 1st Stage Housing
Yes, smart flow sensor
Unavailable in most systems
Easy visual inspection
Daily Production
75 GPD (reliable output)
Often lower or overstated
Reliable daily production
Replacement Filters
Widely available & affordable
Hard or harder to find
Lower long-term cost
Installation
DIY friendly, no plumber needed
Can be more complex
Faster & easier set-up
Support & Warranty
Responsive support + solid warranty
Varies widely
Better post-purchase experience
Value for Money
High performance at competitive price
Higher price for similar specs
Better cost-effectiveness

Reviews

Support

How to install
How to use