In the upper limb rehabilitation field, assisting to various patients per day, in different kinds of therapies is an exhausting task which can be achieved in a semiautomated or automated manner. The ExPro is an exoskeleton of 3 degrees of freedom designed and created to support rehabilitation treatments for patients with little or no mobility in their arms. The device consists in a machine able to move forearm and wrist according to prone-supination, ulnar and radial deflection and flex-extension of wrist movements. The proposed prototype was designed to assist therapists in the first step of rehabilitation treatments, thus, passive therapies. Each mechanical component was designed in the Inventor 3D software and printed on PLA materials (polylactic acid). The controlling step is a Raspberry Pi 3 that receives information, interprets and connects power, and control PCBs. The design and calculations were tasted with the finite elements tool of inventor software. The work result presents an exoskeleton prototype easy to operate and transport, safe for the patient and able to carry out several preprogramed movements.