Crafted from optical grade artificial , ensuring superior light transmission and durability. Features a λ/4 surface type at 633nm, providing exceptional flatness and precision for critical optical applications. <30 arcseconds guarantees minimal distortion, making it ideal for high-precision instruments. Surface finish of 40/20-60/40 enhances clarity and performance, suitable for both square and round configurations. Protective beveling of 0.2~0.5mm at 45° ensures safe handling and installation in various scientific and industrial .