This focusing lens for high power fiber laser cutting machine. Power of laser 2000W-4000W. and laser cutting machine laser cutting machine with PRECITEC fiber laser cutting head. For now, played most of the fiber laser cutting machine (for example, Shenzhen Han's laser, Shanghai United laser, Pentium, Wuhan chutian laser, Jiangsu's leading laser, Shenzhen lightstar laser, Messer, and so on) can be used