The goggles have a very high, for airsoft conditions, value of the hardness coefficient of the lenses - F. It expresses the mechanical resistance of the material. In this case, we are dealing with resistance to so-called low-energy impacts. The lenses are designed to withstand the impact of a steel ball with a diameter of 6 mm and a weight of 0.86 g moving at 45 m/s. In conversion, this translates into a kinetic energy of 0.87 J.
The optical class of glazing is determined by its optical performance. Eye and face protection is divided into 3 classes. Glazing in optical class 1 is designed for continuous use (so these glasses can also be used as sunglasses or safety glasses for everyday use), while glazing in class 3 is designed for short-term use.

• What is EN166?
  
  The EN166 standard applies to all types of personal eye protection used to protect against the various hazards that may be encountered in industry, laboratories, school buildings, DIY, etc., where damage to the eye, or impairment of vision, may occur, with the exception of radiation of nuclear origin, X-rays, laser emissions and infrared (IR) radiation emitted by low-temperature sources. The specifications of this standard do not apply to eye protection where separate and complete standards exist, such as laser eye protection, sunglasses for general use, etc., provided that these standards refer to this standard. Eye protectors fitted with corrective lenses are not excluded. Tolerances for focusing ability and other characteristics in correlation with corrective measures are detailed in ISO/DIS8980-1 and ISO/DIS8980-2.
  
  NOTE!
  
  The above product is of the highest quality and has undergone strength tests appropriate to its resistance class. The manufacturer guarantees the resistance to impact of solid objects within the scope of the resistance class or certificates obtained. Nevertheless, in the event of an inadequate fit, the use of this protection does not exclude the occurrence of injury, for example, through a ball falling under the protective glass as a result of a ricochet. Therefore, before use, it is recommended that the eye protection is adjusted to the individual user's needs. The protective properties of the product may also be altered by improper use and maintenance of the above product, e.g. by cleaning the lenses with unsuitable preparations. The retailer will not be held responsible for any injuries resulting from improper fit and use of the above product.
  
  Manufacturer Bollé Optical
• Class 1 Hardness Factor 
• Thermal protection 100% UV protection
• Glass colour: tinted Smoke
• Certificate EN166-F, 5-3.1, 1FT
• Weight 25g