Our 4 Wavelength Machine has the Best Technology for Removing Unwanted Hair. It shoots a laser beam with 4 wavelengths (755 nanometers (Alexandrite), 808 nanometers (Diode), 940 nanometers (Infrared) & 1064 nanometers (Nd:YAG)). Alexandrite is the best laser for White Skin Color, White, Gray, Blonde & Red Natural Hair Color, Thin Hair and Shallow Depth 1mm to 2.5mm Hair (Upper Lip & Eyebrows). Diode is the best laser for Yellow to Light Brown Skin Color, Brown & Black Natural Hair Color and Medium Depth 2mm to 4.5mm Hair (Legs, Arms, Cheeks & Beard). Infrared is the best laser for Medium Brown Skin Color, Black Natural Hair Color and Medium Depth 3mm to 4.5mm Hair. Nd:YAG is the best laser for Dark Brown to Black Skin Color and Black Hair.