iSpring 2-Stage 6 Month Water Filter 2-Pack Carbon Block Whole House Replacement Filter in the Replacement Water Filters & Cartridges department at Lowes.com
10 Inch Carbon Block(cto) Water Filter Replacement Filters 5 Micron- Under Sink And Reverse Osmosis System-coconut Shell - Water Filter Parts - AliExpress
Amazon.com: Activated Carbon Block CTO Water Filter Replacement – 5 Micron, 10 inch Filter – Under Sink and Reverse Osmosis System (1 pack) : Tools & Home Improvement
Whole House Filter | 20" Big Blue Carbon Block Cartridge | RONAQUA