Using high quality material, the material has the characteristics of low optical transmission loss, low absorption, and high power. The condensing spot is stable, the cutting and engraving effect is good, it can withstand high power density, and the surface film is firm, not easy to fall off, and resistant to wiping. Exquisite processing technology, double-sided anti-reflection coating, cylindrical polishing increases the transmittance. Install the focusing lens with the convex surface facing upwards. After replacing the lens, you need to fine-tune the lens barrel up and down and fix it at the best effect position. Note: Pay attention to the following points when using it to prevent the lens from bursting and prolong the life of the lens: A. The air-cooling failure of the machine causes the lens to overheat and burst, or the air-cooling is not smooth, and there is condensed water in the lens barrel on the lens, causing the lens to burst. B. The anti-spraying liquid containing the material to be engraved on the lens will easily burst if heated unevenly for a long time. It is necessary to clean it up with a cotton swab dipped in absolute alcohol in time. C. When dimming, the light path hits the junction of the edge of the lens and the lens barrel, which may cause bursting. Name: CO2 focusing lens Design wavelength: 10.6m Diameter tolerance: +/0.1mm Thickness tolerance: +/0.13mm length tolerance: less than +/2% Beam deviation: less than 3 arc minutes Customs clearance: 90% transmittance: 99.5% colour:Yellow Material:Zinc selenide size: Diameter 20mm, length 63.5mm Package Contents: 1 x condenser lens Only the above package content, other products are not included. Note: Light 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.