The handheld welding head for laser welding machines consists of the following key elements:

1. Focusing Lens: The focusing lens is responsible for concentrating the laser beam onto the welding point. It ensures that the laser's energy is focused to a small spot size, resulting in high power density and efficient welding.

2. Nozzle: The nozzle surrounds the focusing lens and serves multiple purposes. It protects the lens from spatter and debris generated during welding and also helps to maintain a stable and consistent flow of shielding gas around the weld area. 

3. Adjustment Mechanisms: Handheld welding heads often have adjustment mechanisms to control the focal length of the lens or the position of the nozzle. These adjustments help fine-tune the welding parameters to achieve optimal welding results based on the specific application.

4. Beam Delivery System: The welding head is designed to efficiently deliver the laser beam from the laser source to the focusing lens. This involves using fiber optic cables for fiber lasers.
   
    

   Specifications

   Focusing Lens: 20*3.0 F150

   Collimating Lens: 20*50 / D16*F50

   Protective Lens : 20*2 mm