This is the SixPad Knee Fit: an EMS thigh training system that targets muscles surround your knees. It works on your quads to help you develop stronger knees. It has eledyne fabric electrodes and delivers 20Hz pulses. 20 intensity levels are available for you to try.
The SixPad Knee Fit weighs only 68g. You simply have to use this for 15 minutes a day.