The saxophone is a wind instrument, usually made of brass, but having characteristics more closely related to the woodwind family than to the brass family. It uses a reed, like a clarinet, but a conical bore like an oboe, and a bell shape at the end. In all but the smallest soprano saxophone, the instrument folds over just before the flared bell. 

There are 3 saxophone sizes in common use today,  Alto in Eb, tenor in Bb, and baritone in Eb. When the Eb alto saxophonist plays what is written as middle C, it sound the Eb below middle C. The baritone is one octave lower than the alto. The range is 2 octaves