Manufacturer's part #02 MLQ 001. Original price for the set of 4: $628.00. Non-aluminized 12.5-mm Square Mirror. Material: Fused silica. 6mm thick, wavelength range is visible, near IR 400-800nm. Surface quality is 60-40 scratch and dig. Could be aluminized to make a high reflection mirror or used as a mirror in applications where only a small amount of reflection is wanted such as sun reflection or certain laser applications. You will receive (4) in the case for our low price!