Every laser cutting, welding and drilling system consist of multiple optical components. Being one of the simplest optical components of the system, protective windows at the same are time crucial for securing smooth operation of laser system. Protective windows are highly recommended for shielding more expensive optical components like focusing lenses from splatter and debris during laser processing. All windows are laser grade polished and made of high purity fused silica, thus are suited for usage under power rates exceeding several kW. Anti – reflective (AR) coatings help to prevent back reflections of a laser beam and increase processing efficiency. While uncoated windows reflect 3 % of light per surface, AR coated windows reflect only 0.1 % - 0.2 % per surface. Laserand presents list of lens protective windows for most of commercially available industrial laser machines.