Particularly useful for peeling and cleaning rounded vegetables and fruit: this WÜSTHOF Ikon 3" Peeling Knife - also known as a Turning or Tourne Knife - with its short. bird's beak-shaped curved blade. makes it easy to peel produce such as potatoes or apples quickly. preserving the valuable vitamins found directly under the skin. The straight edge of the Peeler / Tourne Knife enables very precise cuts. making it the ideal helper for hollowing out and decorating fruit and vegetables.