No, both sides of the window are identical, so it doesn't matter which side faces the laser.Related ArticlesWhat is the difference between the laser safety face shield and the laser safety welding face shield?Transparent Laser Safety Windows vs Laser Window Coverings: What Should You Use?Why Laser Safety Windows Often Need to Change When a Machine’s Laser ChangesWhat Is a Laser Safety Window?Does a Laser Safety Window Need the Same Optical Density as Laser Safety Glasses?