This two pack offers both a full red and full orange pair of over-glasses, along with a strap cord and dust bags. They are designed to block blue (and green light, which has similar effects as blue light). Blue and green light are emitted naturally in the visible light spectrum from the sun, but modern technology has up exposed to significantly higher levels at wrong times of the day. This increase in exposure to blue and green light affects our health negatively - primarily through sleep by preventing the release of melatonin. Melatonin is a sleep hormone that allows the body to enter a deep and restful sleep. Blue light stimulates the release of our stress hormone, cortisol, from our adrenal glands which not only keeps us awake but contributes to other health issues like depression, anxiety, obesity, infertility, diabetes even cancer. It is important to block the blue (and green) light from our eyes during periods where we would not naturally be exposed to it. The orange lenses block 99% of blue light from entering our eyes. They are designed to be worn in the late afternoon and into the evening, anytime under artificial lighting or while looking at screens from computers, TVs, tablets and/ or phones. The red lenses block 99% of blue AND green light. They are designed to be worn within the final one to two hours before bed to help stimulate the production of melatonin and suppress the release of cortisol. This newly improved eyewear is designed to be worn over your prescription reading glasses. The wide design of these glasses is made to accommodate most face shapes & sizes as well as offers coverage for most prescription glasses and readers. It will not fit over very bulky frames. It may take a few sessions wearing the glasses to get used to the colour. Shorter sessions in the beginning will help you adjust easier. It can take between 7 to 10 days for noticeable improvements to sleep.Our glasses are worn as PRE-SLEEP glasses and are not for use while sleeping