This is a PLCC-25.4-25.8-C, a Plano-Concave Spherical Lens with a 25.4 mm diameter, sourced from CVI Laser Optics. The lens is made of N-BK7 Schott, a high-quality optical glass, and is designed for laser applications with a wavelength of 588 nm.
The lens features a concave shape with a radius of curvature of -25.8 mm and a center thickness of 3 mm. The effective focal length (EFL) is -50 mm, indicating that it is a diverging lens. The lens is uncoated, which means it does not have any anti-reflective or other coatings.
The lens is in stock and you can find more detailed specifications in the provided link: https://www.idexot.com/media/wysiwyg/cms-pages/pdf/2-Spherical_Lenses.pdf
This lens is suitable for applications that require a diverging lens, such as in laser beam expansion or beam shaping. Its high-quality N-BK7 Schott material ensures excellent optical performance and durability.