Magic Light Therapy Belt for Joint Health

This is a belt my son received as a salary gift. I wondered if it would have any effect. But after using it about twice, the legs that had been stiff and swollen started to feel less painful and more relaxed. I heard that when you plug in the electric cord, it emits light. It supposedly emits three types of light: LED, near-infrared, and far-infrared. I heard that even horses at the riding stable use this product when they get injured.