[]: The 20mm CO2 Laser-lens is made of CVD Znse material, precision polishing and grinding process, high temperature resistance, Laser-pass rate up to 99.9%, reducing Laser-loss, and excellent optical performance. It is a very good CO2 Laser-lens []: The 20mm Laser-lens is designed with double-sided solid coating, which is scratch , , long service life, and ensures excellent scratch resistance. [Wide range of application] The CVD Znse 20mm Laser-focus lens can be used in 30W-200W CO2 Laser-engraving and cutting machine to achieve more creativity and more accurate production. [Product parameters] Diameter: 20mm/0.79 inch; length: 50.8mm/2 inch; Thickness: 2. mm/0.07 inch; shape: meniscus. Laser-lens is suitable for Laser-wavelength=10.6um. Material: Zinc selenide colour: gold Package Contents: 1 x Laser-engraver Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.