This is a ZnSe Flat Window, offered by Alkor Technologies, with a diameter of 25.4 mm and a thickness of 4 mm. The window is made of ZnSe material, specifically identified as 'znse marple-1964' in the Material ID.
The ZnSe Flat Window is designed for use in the 10600 nm wavelength range, making it suitable for a variety of applications in this spectrum. The window is uncoated, which means it does not have any additional layers to enhance or alter its optical properties.
The window is shaped as a thin lens, which is a type of lens with a very small focal length compared to its diameter. This shape is often used in optical systems where a wide aperture and small thickness are required.
For more information about this product, including pricing and availability, please refer to the vendor's website at http://www.alkor.net/ZnSe_windows.html. The link has been verified and is currently in stock, according to the 'weblink status' provided in the item data.