Acrylic Sheet Fresnel Card Magnifier, 2x 4x Magnification, supplied in a PVC pouch
Square Fresnel Lens with an additional conventional round magnifier. Perfect Pocket Size: 8 x 5cm.
A Fresnel lens allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design.
A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases, as in this item, taking the form of a flat sheet.