Highlights: • Muscle strengthening • Relieve soreness • Prevent wasting muscle atrophy • Relax one's muscles • Muscle relaxation • Beauty conditioning Specifications Product size: 15*6*6.5cm Weight of controller: 28g Adjusting gear: 8 modes, 19 levels strength. Charging time: 1H Working time: 160 minutes What is EMS technology? Electrical muscle stimulation (EMS), also known as neuromuscular electrical stimulation, uses electrical impulse to induce multiples muscle contractions. The central nervous system contracts muscles; EMS has been proved to be an active muscle strengthening tool.