This paper introduces a novel underactuated anthropomorphic gripper for prosthetic applications. In order to extend the grasping capabilities of underactuated prosthetic grippers and improve the force transmission ratio, a mechanical lever is mounted inside the palm that allows a proper distribution of the forces and provides mechanical advantage. A static model is developed and the possibilities offered by the lever transmission are investigated. Also, a compact mechanism is introduced to synchronize the motion of the four fingers. Additionally, a mechanical selector is designed that functions as a means of mechanically programming the motion of the fingers by selectively blocking their closing motion. Finally, a prototype, including all the above features, is described and experimental validation is briefly reported.