An EMS muscle training device utilizing EMS technology, featuring 19 levels of intensity adjustment and 8 training modes. - Model Name: EMS MUSCLE PACK IV - Function: Muscle contraction and relaxation via EMS technology - Intensity Adjustment: 19 levels of intensity - Training Modes: 8 training modes - Automatic Training Time: Approximately 20 minutes. Accessories: Instruction manual. A USB AC adapter (sold separately) is required to use this product, but it is not included. I will include a spare USB adapter (white) from my home as a bonus. I used it 4-5 times, but it was different from what I expected.