iPhone 6 / 6s 4.7in Edge to Edge [3D Curved Full Cover] GPEL Real Tempered Glass Screen Protector [Anti Blue light], Replacement Guarantee in Korea] 100% Satisfaction Guarantee (White) Light at night is bad for your health, and exposure to blue light emitted by electronics and energy-efficient lightbulbs may be especially so.  Harvard Health Letter Like to be on your phone before you go to bed at night? Wake up groggy and unrested? Heres the rundown: According to the National Center on Sleep Disorders Research, sleep-related problems affect 5070 million people in the US. A study by John Carroll University found that wearing a blue light filter at night lead to improvements in ADHD symptoms and sleep disorders. Exposure to blue light, while beneficial and even necessary during the day, suppresses the release of melatonin which disrupts the bodys circadian rhythm and can even lead to breast and prostate cancer, diabetes, heart disease and obesity. A simple blue light filter at night can prevent these effects, giving you better sleep, less susceptibility to depression, Seasonal Affective Disorder and cancer. Do yourself a favor and cut the Blue. GPEL 100% SATISFACTION GUARANTEE: We won't waste your time with abstruse guarantees. Contact us immediately if there are any issues and we'll send you another until you are satisfied, simple as that.