Wheeled Magnifier Floor Lamp - Extra Strong - 5 Diopter(with a Extra Clamp) Powerful magnification and illumination with mobility--rolls Precision-ground optical-quality 5"-diameter 5 diopter glass lens: Sturdy 4-leg stand with swivel casters, 34" spring-loaded flex-arm allows perfect positioning Efficient 22-watt circular fluorescent tube produces bright, non-glare task lighting with less heat Infinite-position arm with swivel head, adjustable tension to lock in place