Feature:1. METAL MATERIAL: Our modules are made of hard metal, which is compressive and wear resistant, and will not be deformed for a long time.2. STRONG COMPATIBILITY: This module has strong compatibility, can be used with most laser engraving machines on the market, and has a long service life.3. EXQUISITE DETAILS: The details of this module are exquisite, the edges are free of burrs, the size is precise, and the quality is guaranteed with care.4. PERFECT REPLACEMENT: Due to the precise size of this module, it is a perfect replacement for old or broken accessories on your engraving machine.5. MAIN APPLICATION: This module is mainly used for laser cutting machine mechanism parts to adjust the focal length of the laser head.Specification:Item Type: CNC Laser Head ModuleMaterial: MetalStroke: Approx. 80mm / 3.1inFunction: Adjust the focal length of the laser head.Package List:1 x CNC Laser Head Module1 x Open End Wrench2 x Hex WrenchNote:Please allow 13 mm error due to manual measurement. Thank you for your understanding.