Nearly all soprano and piccolo clarinets have keywork enabling them to play the E below middle C as their lowest written note (in scientific pitch notation that sounds D3 on a soprano clarinet or C4, i.e. concert middle C, on a piccolo clarinet), though some B clarinets go down to E3 to enable them to match the range of the A clarinet. On the B soprano clarinet, the concert pitch of the lowest note is D3, a whole tone lower than the written pitch. Most alto and bass clarinets have an extra key to allow a (written) E3. Modern professional-quality bass clarinets generally have additional keywork to written C3. Among the less commonly encountered members of the clarinet family, contra-alto and contrabass clarinets may have keywork to written E3, D3, or C3; the basset clarinet and basset horn generally go to low C3.