Parameters Material CVD Znse/ ll-VI Znse Transmittance ≥99.8% Diameter Tolerance +0 / -0.13mm Thickness Tolerance ±0.25mm FL Tolerance 90% Surface Figure <λ/2 per 1" Dia AR/AR Coating R<0.5% per surface Compatible Power 40W-200W Attentions: Double-sided solid coating, wiping resistant, extended durability, precision slicing polishing and grinding processes, high temperature laser resistance, excellent optical properties, high working efficiency. Laser transmittance can be as high as 99.8%.Normally, the short focal length is suitable for engraving. If used for cutting, we suggest to work with long focal length.Causes of lens broken and tips: (1) Ensure that the air cooling is good, otherwise the temperature will be too high and the lens will overheat and crack (2) There are condensation water drops in the lens barrel, which may cause the lens to break. (3)The lens is stuck or pollute with the jets of the cut or engrave material, Uneven heating for a long time is easy to cause broken. It should be cleaned with cotton ball dipped in absolute alcohol or acetone in time. (4) When adjusting the light path, the light path is not correct, the laser accidentally hit the edge of the lens and the junction of the lens barrel, resulting in broken. About Lens Shape Focal length is the distance between the lens and the workpiece(material being cut or engraved). Before replace or install the lens, please confirm the diameter and focal length firstly. It is recommended to use convex upward, flat or concave facing the engraving or cutting material. Laser Lens and Laser Mirrors PVD ZnSe Laser Lens Add to Cart CVD ZnSe Laser Lens Add to Cart GaAs Laser Lens Add to Cart Si Laser Mirror Add to Cart Mo Laser Mirror Add to Cart Cu Laser Mirror Add to Cart Customer Reviews 4.6 out of 5 stars 417 4.6 out of 5 stars 433 5.0 out of 5 stars 5 4.6 out of 5 stars 270 4.9 out of 5 stars 7 3.7 out of 5 stars 22 Price $22.39$22.39 $30.59$30.59 $35.00$35.00 $37.90$37.90 $33.99$33.99 $68.60$68.60 Diameter 12/18/19/20/25mm 12/15/18/19/20/25/30mm 18/19/20/25mm 19/20/25/30/38m 20/25/30/38mm 20/25/30/38/50/60mm Material PVD ZnSe CVD ZnSe GaAs Silicon Molybdenum Copper Power Max. 150W Max. 200W Max. 200W Max. 200W Max. 200W Max. 500W Wavelength 10.6um 10.6um 10.6um 10.6um 10.6um 10.6um Coating ✔ ✔ ✔ ✔ ✘ ✔ Shipping Amazon Amazon Amazon Amazon Amazon Amazon