Moen shower faucets are identified in several ways. If you need to replace the handle or cartridge, making a positive identification of the model of Moen faucet you own is necessary before you buy the parts. If you purchase the wrong parts for another model, they will not work in your faucet. You won't need a plumber or contractor to get this job done. With simple tools and about a half an hour, you can do it yourself.
Turn off the water to the faucet to prevent accidental leaks. Access the water pipes through the access panel in the shower wall, or shut the main water pipe to the home.
Look for the Moen marking on the trim plate or handle of the faucet to first identify it as a Moen product. Once you confirm this is a Moen faucet, go to the manufacturer's website (see Resources) and select the "bathroom" button. Then choose "faucets" and then "shower faucets" on the subsequent pages.
Compare your faucet with the faucets on the page and identify it through a visual match of the handle and trim piece. Select the faucet similar to yours, and choose the "Exploded Parts View" link on the product page.
Take the handle off the faucet by removing the cap on the handle and taking out the set screw with an Allen wrench, and then pull the handle off. Take out the clip or retaining nut if it is an older faucet, or remove the stop tube kit (on newer faucets) with large or small pliers. Compare the parts on your faucet to the part's diagram on the product page.