For use in all American Standard(R) Actuator Flush Valves. The Fluidmaster 5103 American Standard Actuator Seat Disc is designed to fix and upgrade your American Standard Toilet Seat Disc. Built for versatility this model will work with snap-on, or thread-on models, and comes with a brass screw-on adaptor. The high quality rubber disc is rigid to ensure a proper seal with every flush and provide a long lasting solution. Quickly upgrading faulty, or corroded American Standard Seat Discs is simple with this easy to install design.