Feature:  Fusion of modern biotechnology, high quality massage pen, good for health promotion. Electric magnet therapy without piercing the skin to do acupuncture. Simple operation, easy to carry. Safe and effective, with no side effects. Affordable family use.  Specifications: Type: Massage Pen Power: 1 x AA Battery (Not Included) Main Color: Silver Material: Magnet, Alloy Features: Magnet Therapy, Health Promotion, Modern Biotechnology Size: 20cm x 3cm/7.87" x 1.18" (Approx.) Package Included: 1* Massage Pen(Without battery, you need to buy it yourself) Tips:Without battery, you need to buy it yourself Please Note:  Treatment principle of  Electronic Acupuncture Pen  is used electrical pulses to to stimulate acupuncture points then to activate cell and dredging the channel, while there is a condition to generate the electrical pulse,that is,current's positive and negative poles must be turned on. The pen is a monopole current(the nib) output, so the other pole current should be conducted by hands and form circumfluence with the nid of the  Electronic Acupuncture Pen ,so that it will produce electrical pulses.So it is normal to feel a little numbness of the holding hand, it is how the meridian pen works, not quality problem. In the current return process, depending on the size of the hands'resistance value,the strength you feel will be a little different.Some people would feel more strong and some will feel weak. Young people or health people will feel a little stronger. Elderly or in poor health people will feel weak.  Phenomenon like "Electric leakage, Electric numbness, Electrical Stimulation" of Electronic Acupuncture Pen,like discussed above,is not quality problem, but its treatment principle.