This is the 20SD520ER.2, a 50.8 x 50.8 mm Borofloat 33 Economy Broadband Metallic Mirror with a thickness of 12.7mm. This mirror is sourced from MKS/Newport, a renowned vendor in the optical industry.
The mirror features a protected silver coating on the front, specifically the New ER.2 coating, which is designed to provide high reflectivity across a broad spectrum, from 480 to 20000nm. This makes it a versatile component for various optical applications.
The mirror's rectangular geometry and thin lens shape add to its functionality, providing a robust and adaptable optical element. The mirror is made of Borofloat 33, a glass material known for its excellent thermal properties and chemical resistance, making it suitable for harsh environments.
For more information and to check its availability, you can visit the vendor's website through this link: https://www.newport.com/p/20SD520ER.2. The link has been verified and the mirror is currently in stock.