Stroke is the main cause of permanent and complex long-term disability in adults. RETRAINER S2 is a system able to recover and support person’s ability to perform Activities of Daily Living (ADL) in early stage after stroke. The system is based on exercises for hand and wrist performed using Neuro Muscular Electrical Stimulation (NMES). This work describes the preliminary results of a multi-center Randomized Controlled Trial (RCT) aimed at evaluating effectiveness of the system. The preliminary results were calculated on 18 patients who completed the protocol. Data is promising, the RETRANER S2 system seems to be a good tool for stroke rehabilitation. Data confirms also a general good usability of the system.