The Atomstack Window Lens is a high-quality, durable lens designed specifically for use with Atomstack laser models such as A20, X20, A30, X30, and A40. With an output power of 20 and above and a wavelength of 450nm, this lens is perfect for precise and accurate laser applications. Made in the United States by Atomstack, this lens is a reliable and essential accessory for your laser setup. With 1 lens included, you can ensure that you have a spare on hand for any maintenance or repair needs.