The NDUV213B is a Neutral Density Filter from Thorlabs, designed with a base shape of 50 mm x 50 mm and a thickness of 2 mm. This filter is part of the UVFS family, specifically identified as UVFS Mal-1965, and features a thin lens shape.
The NDUV213B is coated with THo NDUV OD13 on both the front and back surfaces, providing a neutral density that reduces light intensity without altering the color composition of the light source. This specific filter has an Optical Density (OD) of 1.3, which corresponds to a 40% transmission of light.
The catalog number for this item is NDUV213B, and it is currently in stock. You can find more information about this product, including pricing and availability, on the Thorlabs website at https://www.thorlabs.com/thorproduct.cfm?partnumber=NDUV213B.