Size: 147*145*31mm. Weight: 90g. * Use optical principle and high quality optical materials, prism turns page 90?, help people easy to read books, watch TV or do other things while lying flat. * Strict material selection and precision processing, internal reflection prism equivalent in glass plate, so there is no influence to the user"s vision. * Simple use and maintenance, high quality, makes the user feel comfortable, distinct and bright, has got the consistent high praise. * Have obvious effect in preventing and alleviating cervical spine, lumbar spine and shoulder fatigue and discomfort.