Donatello, nickname Don, Donnie or Donny, is a fictional character and one of the four main characters of the Teenage Mutant Ninja Turtles comics and all related media. He is co-creator Peter Laird's favorite Turtle.
He is usually depicted wearing a purple eye mask. His primary signature weapon are his (2) effective bō staffs. In all media, he is the smartest of the four turtles. He is listed as 4' in height on the original action figure release Donnie often speaks in technobabble with a natural aptitude for science and technology. He is the middle & second youngest of the turtles. Like all of the brothers, he is named after a Renaissance artist; in this case, he is named after Italian sculptor Donatello.
Source: Wikipedia, "Donatello (Teenage Mutant Ninja Turtles)", available under the CC-BY-SA License.