Instantly turns prescription or safety glasses into magnifiers for close up work. Pivots out of the way when not needed. Attaches to either right or left side. Precision-ground optical glass.
Big Book Catalog, Issue:69, Page:390
Big Book Catalog, Issue:69, Page:446
SPECS: 24mm dia. Power/Focal Length: #3 - 3X, 3½" (9cm), (best for gunsmiths).