The SLB-25B-80P is a 25.0 mm diameter double-convex lens with a focal length of 80.6 mm, sourced from OptoSigma. This lens is made of n-bk7 schott material, a popular choice for its high refractive index and low dispersion. The lens's geometry includes a thickness of 2 mm at the edge and 3.9 mm at the center, with a back focal length of 79.4 mm. The radii of curvature for the first and second surfaces are 83.04 mm and -83.04 mm, respectively. The lens is uncoated, offering a cost-effective solution for applications where anti-reflective coatings are not required. This lens is currently in stock and can be purchased directly from the vendor's website.