What is EMS? The principle of EMS fitness is to transfer the current signal to your muscle directly, The human body recognizes these current signals as human bio-electricity signal. The signal can stimulate muscle contraction and achieve the purpose of reducingfat and slimming. Package includes: Controller Massage belt USB charging cable Manual Notice: To ensure the correct and safe use of the product, please read the manual carefully before use. The precautions described in this manual are intended to ensure the safe and proper use of the product and to prevent injury or property damage to yourself and others. Product details: Package Dimensions :8.7 x 8 x 1.7 inches Belt Size: 13*110cm (waist)/ 41cm(arm) Material : ABS+PU Working temperatur : 10-35 Model(intensity):12(20 level) Working voltage:3.7V/50mA Working time:15 minutes Battery capacity:150mAh Reminder:The host will shut down automatically when massage path have been removed for 10 seconds