This is a Plano-Convex Lens, type SLB-50.8-700PIR1, manufactured by OptoSigma. The lens has a diameter of 50.8 mm and a focal length of 700.0 mm. The lens is made of n-bk7 schott material, a common type of glass used in optical applications due to its excellent optical properties.
The lens geometry includes a thickness edge of 3 mm and a thickness center of 3.9 mm. The inner radius is 0, and the outer radius is also 0. The lens's front and back are coated with opt ir1, a coating that enhances the lens's performance in the infrared spectrum, specifically between 633-1064nm.
The lens's shape is spherical, and it is designed to be used in a circular base shape. The back focal length (BFL) is 697.4 mm, and the effective focal length (EFL) is 700 mm.
The lens is currently in stock and available for purchase. For more information, please refer to the vendor's website using the provided weblink.