Features： 1、Intelligent Modes: 9 levels of heating, 40 DegreeC~56 DegreeC constant temperature heating, and after heating and friction, the massager can release beneficial trace elements, making the skin more comfortable. 2、TENS Pulse: Using pulse frequency conversion technology, the massager brings you three layers of deep massage experience: nerve layer, blood vessel layer, muscle layer. 3、Stress Relief: Layer by layer, the massager can smooth every knotted nerve, deeply release the pressure of the body, and bring a SPA experience to the body. 4、Red Light IrradiationTechnology: Release 600?650nm wavelength red light, penetrate the layer of the skin and directly act on the muscles, helping to relax the deep muscles. 5、Small to Handle: The machine is small and pocket sized, easy to operate and carry. It is very convenient to take and use whether you are at home or traveling. Specification： Item Type: Back Massager Battery type: Lithium Battery Battery Capacity: 600mAh (shipped with built in battery) Applicable Body Parts: Shoulders, back, elbows, abdomen, legs, head, face, neck, chest. Package List： 1 x Back Massager 1 x USB Charging Cable