Kit includes: one 27" x 72" sleep mat, one 15' foot grounding cord, one outlet checker Compatibility: The Ground Therapy Sleep Mat requires a properly grounded, three-prong US-style outlet. Alternatively, you can use a ground rod cord that connects directly to the ground outside instead of using your outlet. If you plan to use your sleep mat outside the United States or Canada and you do not have a ground rod cord, you may need an international outlet adapter with a ground connection. Do not use universal outlet adapters with the Ground Therapy Sleep Mat, because they typically have faulty ground connections, which would prevent the sleep mat from working.