Description Prytec Laser Focal Lens 15mm Diameter is available in 1 focal length; 50.8mm. Prytec Laser Focal Lens 20mm Diameter is available in 4 focal lengths; 38.1, 50.8, 63.5 and 101.4mm. The focal length of a lens is the distance at which the focal point occurs. The focal point is where the laser beam has the highest energy. Lenses that have a smaller focal length are ideal for engraving whilst a lens with a long focal length e.g. 101.4mm are ideal for cutting thicker material
