From Wikipedia
The soprano helicon (in E♭) is a coiled brass instrument from the helicon family.
The design of the modern soprano helicon takes acoustical advantage of the helicon's easy blowing, but is not simply another circular petite bugle or soprano cornet. The helicon clearly has a larger bore and wider tapered conical tube with a large bell for the instrument of its size. The pitch of E♭4 was deliberately chosen, so that musicians can easily play the soprano line within the middle register of the instrument going mostly up to G5. E♭4 was also chosen for its open and piercing nature within the pitched bass winds since it was intended for the Soprano helicon to become a first and leading voice of the family (speaking in terminology of the band, taking the role of 1st Flugelhorn or 1st Cornet and not the role of Petite Bugle, or Soprano Cornet).