56 SMD LED Desk Clamp Magnifier Lamp - Extra-Large 7-inch x 6-inch Lens - 5-Diopter Extra-large 7.5-inch x 6.25-inch rectangular glass lens, optical-quality 5-diopter magnification 56 ultra-efficient, individual SMD (surface mount diode) LED bulbs produce eye-pleasing task lighting on less than 9-watts and about 680 lumens - last 100,000 hours Heavy-duty clamp system holds firm to desk or tabletop up-to 2.5-inches thick without damaging furniture 36-inch triple-joint arm adjusts with feather touch and holds position without springs Power switch located on lamp head for easy access, 72-inch power cord; UL listed