Buckys famous 40 Blinks Sleep Mask is a landmark in the most comfortable, convenient sleep. With a 99% customer approval rating and hundreds of thousands of sleep masks sold, this is the best sleep mask on the market. Block out light and sleep soundly anywhere life takes you! The main reason people sleep is too much light—darkness stimulates the natural melatonin production, which helps you achieve deep, restful, and restorative sleep.