This is a Plano-Convex lens, type SLB-25.4-700PM, manufactured by OptoSigma. The lens has a diameter of 25.4 mm and a focal length of 700.0 mm. The lens is made of n-bk7 schott material, which is a common type of optical glass known for its excellent optical properties.
The lens has a spherical shape with a front surface radius of 363.3 mm and a back focal length of 698.5 mm. The edge thickness of the lens is 2 mm, while the center thickness is 2.2 mm. The lens is coated with Opt M on both the front and back surfaces, which enhances its transmission properties in the wavelength range of 400-700nm.
The lens is currently in stock and available for purchase. For more information, please refer to the vendor's website using the provided weblink.