Features METAL MATERIAL: Our modules are made of hard metal, which is compressive and wear resistant, and will not be deformed for a long time. STRONG COMPATIBILITY: This module has strong compatibility, can be used with most laser engraving machines on the market, and has a long service life. 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. PERFECT REPLACEMENT: Due to the precise size of this module, it is a perfect replacement for old or broken accessories on your engraving machine. 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 Module Material: Metal Stroke: Approx. 80mm / 3.1in Function: Adjust the focal length of the laser head Package List:1 x CNC Laser Head Module 1 x Open End Wrench2 x Hex Wrench Note:Please allow 1‑3 mm error due to manual measurement. Thank you for your understanding. Package List 1 x CNC Laser Head Module 1 x Open End Wrench 2 x Hex Wrench