1. Professional Grade Led Light Therapy: 660nm red light therapy is known for its ability to improve skin problems. 850nm near infrared light reaches deeper tissues, helping muscle and improving joint stiffness. 2. Comfortable To Use Product Specialization: Many professional doctors are also using this product with good results. The device has also received international certification. The red light therapy belt fits comfortably over your hand when you are sitting, lying down or walking around. 3. Not Included In The Package: If you do not use power pack, we recommend that you use the power cord with adapter, which uses wide voltage DC 100 240 V, AC 5V2A, which is longer, safer and more applicable, also It can be put in a handbag. 4. This red light therapy device can be plugged into a power source or connected to any portable battery (not included). It is very light and convenient. You can easily enjoy it in the office or at home. It is easy to say goodbye to the troubles of bulky products or inconvenient mobility when connecting the power cord!