The front is acetate: a compound of natural materials, mostly cotton, which feels nice and cool against skin. The lenses, whether clear or sunglasses, are optical quality, and absorb UV. They are made from a highly developed plastic compound — the standard these days, rather than glass (hence these aren't "glasses"). The frame comes in a leather case, made by a small family-run leather workroom in east London. The case is made with thick veg-tan leather — with all the edges hand-buffed — and is lined with the reverse of the same leather to create a sort of soft suede effect. It closes with a tarnished brass Sam Brown fastener.