In 1972, Weather Report released its second album, "I Sing the Body Electric". The first side featured new studio recordings, while the second side was taken from live recordings of a concert in Tokyo, featuring the full-band lineup of Zawinul, Shorter, Vitouš, Gravatt, and Um Romão (and later available in full as the 1972 Japan-only double album "Live in Tokyo"). The studio side used extended versions of the band including various guest performers, suggesting that Weather Report was not necessarily an integral jazz band, but might possibly work as an expandable project set up to realise the music of its three composers. The album also featured Zawinul's first use of a synthesizer (an instrument with which he would become synonymous within jazz) and of sound effects.