The present invention is a switchable gripping terminal device that can be switched from a voluntary open prehension mode to a voluntary closed prehension mode, at will by the user. In an embodiment of the present invention, the terminal device may comprise a movable digit attached to a fixed digit, whereby the user can actuate the movable digit, such that the movable digit rotates relative to the fixed digit. The terminal device may comprise a lever, which enables the user to switch from a first mode, voluntary open (VO), to a second mode, voluntary closed (VC). This switchable biasing means, allows the user to decide the prehension mode, and easily switch the mode at will, according to the circumstances.