This is a 25.4 mm diameter Germanium Flat Window, offered by Alkor Technologies. The window, which has a thickness of 5mm, is uncoated, providing a clear view of the wavelength of 10600 nm.
The Germanium material used in this window is known as Germanium burnett. This material is often used in optical applications due to its excellent transmission properties in the infrared region of the spectrum.
The window is of the flat variety, which means it has a flat, circular shape. This shape is often used in applications where a flat, unrefracted view is required. The window is also thin, which makes it ideal for use in applications where space is limited.
For more information about this product, you can visit the Alkor Technologies website at http://www.alkor.net/germanium_windows_catalog.html. According to the website, this product is currently in stock, indicating that it is readily available for purchase and use.