Check the listing for details. Circular Biconvex Optical Glass Lens 5 Inches. Condition: Used. Listed at 15.00 USD. The product is a 5-inch circular biconvex optical glass lens. This lens is a type of optical collectible item that can be used for various scientific and medical applications. With its unique design and high quality material, this lens can be a valuable addition to any collection focused on optics or scientific equipment. Perfect for collectors or those interested in optical technology, this lens offers a glimpse into the world of science and medicine through a visually intriguing and historically significant piece.