This Heath Zenith White Wired Door Chime Kit SL-27102 offers convenience and reliability in one package. It comes pre-assembled with a 2-note chime, transformer, 1 lighted button, and 1 unlighted button. Made of plastic, the 4" x 7.25" x 2" chime is cULus listed and perfect for homes and businesses. Start using it right away with no assembly required.