This arm muscle trainer can help to tone, tighten and strengthen your arm muscles and relieving symptom for tighten shoulder and neck. You will be surprise by the unexpected result after trying out.   Feature: A set include: 2 host to change mode and 2 arm muscle toning belt.  Electric muscle stimulator is to transfer the current signal to muscle directly which close to the current strength of our body, promoting muscle movement and making the muscles be in the state of training.  Thin and lightweight design so that you can have your muscle training not only in the gym, but also in office during your work and in home while you do the housework.  6 work modes and 10 levels of intensity for your training demand.  12 minutes working time, the host will off automatically after 12 minutes.  Adhesive gel pad will stay in place which allows full movement.  Great to help relieve symptom for tighten shoulder and neck while promote your muscle movement.   Specification: Material: PU & ABS;  Battery: 2 * AAA (not included);  Frequency: 1-100HZ;  Using mode: 6;  Working time: 12 minutes;  Size: Arm training belt: 20 * 5.5cm / 7.8 * 2.3in;  Host: 8 * 6cm / 3.1 * 2.4in;  Package weight: 84g / 2.9oz;  Package size: 22 * 19.5 * 3cm / 8.7 * 7.7 * 1.2in;