F Flammi Prism Glasses is great for using a laptop or reading a book in bed while lying flat. Changing the sight perspectives of wearer, breaking the rules of watching things, allowing users watch the images in front of them naturally, conveniently, comfortably and distinctly in a lying position Fit for men and women Extremely beneficial to people's physical and mental health Amazing glasses can effectively prevent and lessen the fatigue and discomfort of the neck, the lumbar vertebra and the shoulder portion. SpecificationsMaterial: premium plastic frame, Metal hinge, Glass lens Color: Black Item weight: about 3oz (86g) Leg length: about 5.5" Frame height: about 1.6" Frame width: about 6.3" Bridge: about 0.5" (12mm) Nose Distance: 18mm distance between two centers of inside lens: about 2.6"/6.8cm Please Note1.These glasses are to be used for a short periods of reading only. Please remove the glasses before falling asleep. Do not wear while walking/in motion as they can be disorientating. 2.Since the lens is prism that made of glass, the bed eyeglasses is kinda heavy. Just do not wear it too long. Package 1 x Prism Glasses