These systems connect to the plumbing below a kitchen sink. Some use a dedicated drinking-water tap; others feed the existing faucet. Match the model and service flow to the way you plan to use filtered water.
A carbon filter’s gallon rating and its list of certified claims are separate facts. Check both, along with the cartridge and the time limit for replacement.
Open a system to see the exact replacement items, each captured claim and its source. Check rated flow against the intended use and use the replacement calculator to enter your own daily volume and purchase prices.
Not every source specifies the same test limits. A reviewed manufacturer sheet and a checked registry entry are labeled separately. An unlisted claim means it has not been captured here.