The hardest part of changing this was finding the tiny Allen wrench needed in my tools to remove the faucet cover to access the cartridge. After that , turn off water, remove the nut, use pliers to grab the old cartridge , wiggle and pull. The old one was plastic and had broken so needle nose to pull out the base. Then install new. Note to “clock” the new to make sure the handle is in the right position . (Pointing the correct way)