Abstract : In this paper, a novel 2-DOF robotic wrist mechanism which has a large size hollow space with a reverse motion transmission is introduced. The proposed wrist mechanism is consisted of a stacked two mirrored shape 5R spherical parallel mechanism structure by using the reverse motion transmission from a 5R module to another 5R module. Based on the design of the proposed wrist, it has both a wide workspace and a large hollow space compare to the other robotic wrist mechanism developed. The kinematic model and its characteristics are analyzed and the implementation of the wrist design with the prototype hardware is addressed in this paper. Finally, simple initial experiments are conducted to verify the feasibility of the proposed wrist mechanism.