Parameter: 20mm/ 0.79inch; Length: 63.5mm/ 2.5inch; Thickness:2mm/ 0.07inch; Transmittance: 99.5%.Weight: 0.1KG High Quality:CO2 Laser Lens with superb double-sided solid coating wiping resistant. Precision slicing, polishing, grinding. Resistant to high temperature, excellent optical properties; long working life, high working efficiency. Laser Lens Shape: Plano-convex( some meniscus shape may mixed together when manufacturing, but it is the same effect as Plano-convex shape). Usage:Focus lens compatible for 40-200W CO2 laser engraving and cutting machines. Colour:As Shown Material:zinc selenide Package Contents: 1 x Laser Lens 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.