The SunSquare+ is a light designed for use by individuals with seasonal affective disorder (SAD). The unit features two light settings and a variable height floor stand. Set to the high setting, model SB-718 provides 10,000 lux at a distance of 27 inches from the user and model SB-699 provides 10,000 lux at a distance of 22.5 inches from the user.. POWER: Model SB-718 uses sandard 110-volt current. Model SB-699 uses 220-volt current for overseas use. OPTIONS: Replacement bulbs. DIMENSIONS (WxHxD): 23 x 24 x 3.75 inches. WEIGHT: 19.5 pounds. WARRANTY: The manufacturer offers a 30-day money-back guarantee and a lifetime warranty on the unit. A two-year warranty is offered on the lightbulb.