The instrument for Esperanza Spalding is a BASS, which is a four-stringed instrument that is part of the string family. It is usually played with the fingers or a pick and is used to provide a low-pitched accompaniment in many genres of music. The BASS is an integral part of jazz, rock, and other popular music styles. Esperanza Spalding is an American jazz singer, songwriter, and multi-instrumentalist who has won four Grammy Awards. She is known for her unique style of playing the BASS, which combines elements of funk, soul, and jazz.