The model name "auth" originates from the word "Authentic". The front part of auth is made of a piece of titanium, which pressed several times to form the front part. Generally speaking, end pieces tend to deteriorate over time. End pieces of auth are screwed because the parts are easily replaceable. Compared with sole, lens height is high and size is one size bigger than sole. Rims around lenses are designed to be thin and delicate. Temples are made of βtitanium to have the flexible function.