*Four massage heads, covering 4-7 cervical vertebra accurately, just covering the common pain area of cervical vertebra. *Tens pulse technology, deep care magnetic physiotherapy; low frequency pulse electromagnetic conduction in the skin, through the activation of human muscle cells, prevent muscle stiffness caused by pain and other conditions, but also on the deformed bone to stimulate bone cells reset. *4D floating massage head, deep fit neck, apply uniform massage; streamline around design, automatically adapt to neck curve, weaken pressure, close to neck, do not slip. *The inner wall pad is skin friendly, comfortable and antiskid; the elastic arm has good rebound and strong toughness; the electrode piece automatically adapts to the neck curve. *Fast charging, long endurance; safe use, save power, will automatically shut down when not in use. Specifications: Product Name: cervical massager Power mode: USB Control mode: computer Rated voltage: 3.7V Rated power: 3W Rated time: 15 minutes Number of massage heads: 4 Product size: 14 * 14.5 * cm Package size: 21.5 * 6.5 * 10cm Massage technique: patting, massage, percussion, kneading Package Included: 1*Neck protector Notes: 1-2cm error might exist due to manual measurements, please kindly understand. The colors deviation might differ due to different monitor settings. We provide you with the best product and service. If you have any problem, please let us know, and we will solve the problem ASAP. Thank you so much.