Proprietary, exclusive OttLite ClearSun® LED - reduces eyestrain by 51% Provides smooth, uniform light with Color Rendering Index (CRI) of 97 3 color temperature modes,Memory feature remembers your last setting for color temp 3 brightness settings with touch controls Maximum lumen output of 428 Two-tone metal design with adjustable shade and counterbalance arm to lock lamp in desired position Height adjusts from 4 to 18 inches with long 10 inch arm (from pole to shade) Base diameter is 6 inches Includes 5V, 2.1A USB port to fully charge smart phones and tablets Energy efficient LEDs rated to last up to 40,000 hours