808 nm near-infrared light can penetrate to a MAXIMUM tissue depth of approximately 3.5-4.5 cm (1.4-1.8 inches). However, the effective depth, the maximum depth at which an effect can still be generated, will be determined by numerous factors, including the wavelength and intensity of the beam(s), the physical design of the applicator, the technique with which it is applied, the tissue tip and condition, and the preparation of the area being irradiated. For this specific device, the effective penetration depth would likely fall between 2.5-3.5 cm (1-1.4 inches), although, since the majority of the output is from the 650 nm visible red laser emitters, the light from which has an effective penetration depth of 1-2 cm (0.4-0.8 inches), the treatment time for deeper-tissue targets will be quite long.