This is a Plano-Concave Lens from Laser Components, designed with a base shape of a circle and a spherical geometry. The lens has a diameter of 12.7 mm and a center thickness of 1.1 mm. The effective focal length (EFL) of this lens is -20 mm, making it a negative lens. The radius of curvature (R1) is -10.3 mm, and both the inner and outer radii are 0 mm.
The lens is made of N-BK7 Schott, a popular optical glass known for its excellent optical properties. It is designed to work with a wavelength of 633 nm. The lens does not have any coating, as indicated by the empty 'coating' field in the item data.
The lens is available from Laser Components, and the link to the datasheet is provided in the item data. According to the vendor, the lens is in stock, ensuring quick delivery for your optical system needs.