Magnifier -Donegan Optical Opti Visor - 2.5 *MADE IN THE USA*OptiVISOR is a precision binocular headband magnifier which permits both hands free and allows three dimensional vision. It can reduce eyestrain. Used by anyone whose profession or craft requires close accurate work. Can be worn over prescription or safety eyeglasses. Optical glass prismatic lenses: Ground and polished to precision optical standardsbevel edged and mounted in an interchangeable plastic frame It tilts: Adjustable pivots allow the visor