Visible red light, at wavelengths from 630 to 700 nm penetrates tissue to a depth of about 10 mm. Light at this wavelength is very beneficial in treating problems close to the surface such as wounds, cuts, scars, trigger and acupuncture points, and is particularly effective in treating infections. 850nm of near infrared light Infrared light(800 to 1000nm) penetrates to a depth of about 50mm and deeper which makes it more effective tor treating the deeper muscle structures, tendons, ligaments, joints and bones.