This paper addresses the conceptual design and the virtual prototyping of a low-cost, under-actuated prosthetic hand. Particular attention has been paid to ensuring that size, weight, and appearance are as similar as possible to those of a human hand, in order to increase user acceptance. The proposed device comprises a total of 10 Degrees of Freedom (DoF) and 4 Degrees of Actuation (DoA), three of which are enabled by employing electric motors and a tendon transmission system, whereas the last DoA is simply manually actuated by the end-user (e.g. using the still-functioning limb). The virtual prototype of the hand allows easy evaluation of the hand's grasping capabilities as well as its maximum gripping force.