This round toilet bowl is designed to work with American Standard toilet tank models 4021.016.021 and 4021.128.021. Purchased with the toilet tank this toilet bowl will form the following American Standard toilet models: 2384.012.021 and 2829.128.021. The American Standard toilet bowl also incorporates a antimicrobial surface called EverClean right into the material to inhibit the growth of stain and odor causing bacteria on the surface. Check out all of American Standards bathroom and kitchen fixtures to see a complete list of lavatory and kitchen products available for your home.