Origin U.S 26 materials.Much big difference edge thickness ensure a long lifespan. Special design for high power laser machine ranges from 150 to 400w. For metal laser cutter and mixture laser cutting machine this is the best choice.
Thickness: 3 mm Diameter :20mm Focal length :63.5mm(2.5")/101.6mm(4.0") Material :US 26 ZnSe materials Structure :Meniscus