MAG-EYES - Can't see when tying on a size-24 trout fly? Problem solved. Award winning Mag-Eyes can be worn WITH OR WITHOUT PRESCRIPTION GLASSES! Weigh virtually nothing, fit comfortably with a slip-on cushioned headband. When not in use, raise the visor. Interchangeable +1.6 power lens (working distance 12"-14") and +2 power lens (working distance 10"-12") let you choose the right strength for the task. Optical-quality acrylic lenses reduce eye strain.