These are high-quality Hastings Triplet Loupes. Hastings lenses are constructed from three lens elements cemented together to form a single lens. The unmatched clarity of these triplet loupes is further enhanced by black outer lens edges which eliminate color distortion. All loupes come in a hard leather case. Loupes are available in a variety of colors with or without a non-slip rubber grip also engravable. Lens diameter is 18mm.