




| Marking EN 166 : 2001 | Marking EN 16321-1 | |
| Refractive power | 1, 2, 3 | No marking If enhanced optical power is claimed, « 1 » can be marked on lens | 
| Increased robusteness/Basic mechanical strength | S | No marking | 
| UV filter | For example 2-1,2 (Formerly EN 170 : 2002) | U 1,2 | 
| Sun glare filter | For example 5-3 ,1 (Formerly EN 172 : 1994) | G3 | 
| IR filter | For example 4-3 (Formerly EN 171 : 2002) | R3 | 
| Welding filter | For example 5 (Formerly EN 169 : 2002) | W5 | 
| Resistance to high speed particles | ||
| 45 m/s | F | C | 
| 80 m/s | - | D | 
| 120 m/s | B | E | 
| 190 m/s | A | - | 
| For extremes of temperature | FT, BT, ou AT | CT, DT or ET | 
| Resistance to high mass impact | - | HM or HMT (extremes of temperature) | 
| Resistance to droplets and splashes of liquids | 3 | 3 | 
| Resistance to dust particles | 4 | 4 | 
| Resistance to fine dust particles | 5 | 5 | 
| Protection against streams of liquid | - | 6 | 
| Protection against radiant heat | - | 7 | 
| Chemical resistance | - | CH | 
| Protection against electric arc | 8 | - | 
| Resistance to molten metals and hot solids | 9 | 9 | 
| Resistance to surface damage by fine particles | K | K | 
| Resistance to fogging | N | N |