New Bausch & Lomb Loupe 3.5X. This is a new Bausch & Lomb double lens 3.5X magnifier. It has a distortion free flat field of view. It is necessary for tool and die making, engraving, biological work, etc. The semi-achromatic lens is mounted in a plastic frame. The lens measures approximately 1 5/8" (41 mm) in diameter with a 3" (76 mm) focal distance.