[MAIN PARAMETERS]: Diameter:19.05mm/0.75", Focal Length:127mm/5", Thickness:2.2mm/0.087" [EAST TO USE]: Applicable power up to 80W-150W,Double-sided solid coating, wipe-resistant, extended durability, frosted edges, easier to install. [HIGH QUALITY MATERIAL]:Hight class USA CVD ZNSE MATERIAL (US II-VI), features in high light transmittance, high temperature resistance, high-speed cutting, etc. [PRECISION PROCESS]: Precision slicing polishing and grinding process, high temperature laser resistance, excellent optical performance, high efficiency, laser transmission rate up to 99.5% [APPLICATION]: Normally, laser lenses with focal lengths of 25.4 mm, 38.1 mm and 50.8 mm are suitable for engraving. If used for cutting, we recommend working with laser lenses with a focal length of 63.5/76.2/101.6/127mm.