iSpring FC15B High Capacity 5-Micron CTO Carbon Block Filter - 10x4.5 for Under Sink & Whole House

Overview

Meet the iSpring FC15B carbon block filter, a high-capacity CTO cartridge designed for both under-sink and whole-house filtration. Built with premium activated carbon, it’s engineered to support consistent water quality across taps while fitting in standard 10x4.5 inch housings. This cartridge is individually sealed to maintain freshness and ensure easy storage when not in use.

What it does

While results depend on your water quality, the FC15B focuses on chlorine reduction, taste and odor improvement, and the mitigation of common organic compounds. Expect crisper water and a more balanced flavor as you continue to filter at home.

• Reduces free chlorine, improving taste and odor
• Targets organic compounds including herbicides and solvents
• Helps mitigate trihalomethanes (THMs) and other contaminants
• Supports steady flow for reliable filtration at home

Longevity and maintenance

Designed for long life, the FC15B can filter up to about 50,000 gallons depending on input water. For optimal performance, replace the cartridge every 6 months or after the recommended volume.

• Long filter life up to 50,000 gallons
• Typically used as the second stage in whole-house systems
• Individually sealed to preserve freshness

Compatibility and installation details

Official replacement for iSpring systems including US21B under-sink filters and WGB21B family units. It also fits other standard 10x4.5 inch housings, making it a versatile choice for multi-point filtration.

• Official replacement for US21B, WGB21B, WGB21BM, and WGB21B-PB
• Fits standard 10x4.5 inch housings
• Individually sealed for freshness and easy storage

Why choose iSpring FC15B

Crafted from premium coconut shell carbon and a tightly packed CTO block, this cartridge emphasizes filtration efficiency and durable performance. It’s free of surfactants, binders, and adhesives, with no carbon ash leaching, and it’s backed by iSpring support for added peace of mind.

Note: Actual performance depends on your source water and system setup. The FC15B is designed to support cleaner-tasting water at every faucet while aligning with common 10x4.5 inch housing standards.