The shape of the "blades" for a Fenestron (e.g. see model EC 135 or Dauphin) differs from those of a conventional tail rotor.
With a total length of 65 mm the pre-finished blade runs a trapeziform from 25.5 mm chord (inside) to 19.5 mm (outside). The unique arched shape of the Fenestron blade helps to handle the extra forces involved.