The Easy-Play Speed Music Musical Marmalade Double-Note Series is a collection of sheet music and songbooks featuring popular songs and musicals that can be played on organs, pianos, and guitars. Published by Sight & Sound International Inc. in the United States, this unit offers a variety of musical arrangements for musicians of all skill levels. The double-note series makes it easy to play familiar tunes with a unique twist, enhancing the musical experience for both beginners and seasoned players.