Flicker-free + Blue light The ultimate solution for the comfort & health of your eyes. Flicker-free monitors with the blue light reducer function substantially reduce the strain & fatigue caused by flickering & blue light emittance of regular monitors. Speakers & headphones Playing with friends? Use the integrated high-quality speakers. Don't want to disturb anybody? Plug your headset into the headphone socket & turn the volume up. Over Drive ON / OFF When very fast graphics are displayed your monitor can sometimes get blurry. Turning on the Over Drive feature will eliminate that. ACR Contrast Ratio is a measurement of the difference between the darkest black & the brightest white your monitor can display. Advanced Contrast Ratio is a feature that automatically adjusts contrast & brightness of the screen to assure perfect picture quality while watching films & playing games..