Just received my product today and excited to give it it a try. The only thing im concerned about is when I set it to the 850 NIR there is no light. Not sure if the belt is defective or not.
This is a very sturdy and well designed device with nice features like a timer, selector for red only, Infrared only or both, and a vibration mode! I have used only a few times, but I am very pleased so far.