These high quality readers let you read naturally, even in complete darkness. Contains two ultra bright lights without any detectable heat. These are great for reading in bed, on a plane, in a car, etc. They are lightweight and comfortable. Standard size lithium batteries are included. The batteries last for up to 100 hours. Available in all common strengths including a 0. 00 no-strength prescription with non-retractive lens. This is a great product for people who want to read without bothering their sleeping partner.