The Y&Y Clip Up Belay Glasses are designed for those climbers that wear spectacles. You just clip them on your own glasses and then you can belay your partner without straining your neck or removing your own glasses to belay.
This model fits on most glasses and sunglasses, and with a small, easy movement you can flip the belay glasses to position them Off and On. The trapezoid-shaped prisms allow you to have a wider vision on the climber without losing the important peripheral vision.
Just clip and belay!