The Airlock mounting system uses a barbed taper at the end of each frame mounting. This precisely matches the inner dimensions of the bushing that mounts within the lens. When the two are pressed together, a secure fit is created that far exceeds that of any other screwless mounting system. Airlock uses pressure rather than screws to keep the lens in place so there is less chance of breakage. The Airlock superior mounting system isn't the only advantage Marchon offers in this rimless collection. Minimal frame componets means lighter weight. This is further optizmized using high quality Beta-titanium to construct the frames. Beta-titanium is the most flexible alloy of titanium. The use of Beta-titanium combined with the Airlock mounting system makes Marchon the leader in premium quality, innovative eyewear.