EN166 The European standard the product is approved against CE European marking B Medium energy impact ( Goggles ) 3 Liquids (droplets / splashes) 4 Dust with particle size of greater than 5 µ m. 5 Gases, vapours, spays, smoke and dust with particle size less than 5 µ m. 8 Electrical arc due to a short circuit in electrical equipment 9 Splashes of molten metals and penetration of hot solids T Protection against high-speed particles at extreme temperatures K Resistance to surface damage by fine particles N Resistance to fogging in extreme temperatures