An EN.166F test means that the frame and lens live up to a low-energy impact standard. The eyewear must withstand the impact of a 6 mm steel ball at 0,86 grams, which is dropped from 1,3 meters at a speed of 162 km/h. The lens must remain in the intact frame and not shatter for it to pass. This is a huge quality stamp when it comes to our performance sunglasses and protective eyewear, as you are guaranteed the same level of protection and quality that the soldiers of the world demand.