Hemiparesis of the upper limb is one of the most serious and most common impairments resulting from stroke. Approximately 75% of the nearly 800,000 strokes that occur annually in the United States cause some degree of upper extremity paralysis. Approximately one-third of stroke survivors develop chronic hemiparesis with significant dependence on caregivers for activities of daily living. Contralaterally controlled functional electrical stimulation (CCFES) is a new treatment designed to improve hand motor recovery through active intention-driven movement combined with repetitive stimulated movement. CCFES stimulates paretic hand opening with a stimulation intensity that is regulated by an instrumented glove worn on the unaffected hand. Therefore, volitional opening of the unaffected hand produces a proportional amount of opening of the affected hand (the paretic hand copies the non-paretic hand), allowing the patient to practice active, repetitive hand opening exercises and functional tasks. CCFES meets the unique demands of stroke patients by incorporating rehabilitation techniques shown to promote neural recovery and boost the brain's capacity to reorganize after injury, restoring motor control of affected limbs. CCFES treatment has been shown in two pilot case studies and in an early-phase randomized controlled trial (RCT) to reduce hand impairment and improve hand function. Ongoing studies include a large RO1 RCT of the efficacy in chronic hemiplegia, a pilot study investigating the effect of adding stimulated elbow extension to hand, an R21 RCT to improve ankle dorsiflexion, and a recently funded RO1 RCT to investigate the addition of stimulated elbow extension to hand. CCFES treatment is a scientifically proven therapy and is expected to have significant commercial potential. However, to achieve successful technology transfer of the lab-based device from single-site research studies to multi-site studies and commercialization, the research-grade device needs to be redesigned for improved manufacturability, durability, and ease-of-use and programming to make it suitable for widespread dissemination. StimDesigns LLC, in collaboration with the inventors of CCFES treatment from Case Western Reserve University, Cleveland FES Center and WIN Enterprises will develop and test the first commercial Hand CopyCat FES system in this Phase I SBIR project. The specific aims are: 1) Design and produce pre- production CopyCat FES systems that meet the design and functional specifications, and 2) Conduct functional, safety and clinical usability testing of the new CopyCat FES systems. This project is a critical step in advancing CCFES therapy and preparing for the first multi-site trail. Commercialization will not only enhance hand recovery after stroke n a desperate population looking for better solutions but also, advance the field of FES rehabilitation research.