Employing the same proven photobiostimulation therapy used in scientists' labs and in salons for more than 20 years, this lightweight, handheld device helps revitalize tired locks for fuller, more lustrous hair. The light energy produced by its safe, low-level laser and four LEDs penetrates scalp tissue to promote increased circulation, resulting in more oxygen and nutrients getting supplied to hair follicles. Equally effective on men and women, simply "brushing" for three 15-minute sessions per week promotes thicker, more vibrant hair, with users typically seeing results in 8-16 weeks. The laser and LEDs are rated for 10 years of service. Two AAA batteries provide convenient cordless operation for up to 6 months. 8" L x 2" W x 1 1/2" D. (5 oz.)