Technical Information - S4 Optics



S4 sunglass frames are made from high quality handmade cellulose acetate. The process of producing cellulose acetate sheets (or zyl) was developed in Italy in 1849. To this day, we follow the same standards and processes to craft the zyl acetate we use for our sunglasses frames.

S4 zyl acetates possess a deep gloss, vibrant colors,  high transparency, superior tensile strength, and lightweight feel. Acetate is made up of a (bio) polymer derived from natural cotton fibers and/or wood pulp. Colors and patterns are developed by skilled artisans through a detailed process that can take hundreds of hours to complete.

Each acetate sheet is made of zyl acetate that is a renewable, non-petroleum, plant-based material, which is also lightweight and hypoallergenic. Multi-level patterns are created through a process of mixing colored organic powders with a transparent paste which is combined by feeding the mixture through rollers which spread the color evenly. The resulting substance of colored patterns is then placed into a mold to create chips which are then pressed into blocks. Patterned sheets of acetate are cut from these blocks and then finally cut to the final frame designs. Each frame is buffed by hand by an experienced technician to a highly polished luster.




Our factory technicians complete the manufacturing process by fastening the temples to the frames with hinges and tiny screws. The hinges are engineered to act as a precision functioning joint between the temple and frame by opening and closing smoothly and effortlessly. Next, the lenses are carefully inserted. Finally, the frame is adjusted, cleaned and inspected.


S4 sunglass lenses are crafted from CR39. Also known as allyl diglycol carbonate (ADC), CR39 is a plastic polymer. It’s optical quality is almost as good as glass, half as heavy as glass, much more resistant to shattering, and still very resistant to scratches.

S4’s X-Glare™ polarized lenses have a polarization layer that blocks reflected glare from your eyes. Polarized lenses help to enhance clarity and provide comfort when outdoors in situations where glare can be more prevalent, such as boating, fishing, driving or skiing.

All S4 lenses provide your eyes with a UV 400 rated shield that prevents dangerous ultraviolet rays from harming your vision and guards against UVA, B and C rays.



Always clean your sunglass frame and lenses with fresh water and your S4 Optic microfiber cloth. You should treat your sunglasses in the same manner as any other part of your wardrobe and clean them after every use. 

DO NOT allow gasoline, fuel (has corrosive additives), sunscreen, bug spray, alcohol, Windex or any cleaner that contains ammonia to come in contact with your sunglasses. These chemicals are damaging to the lenses and frames. Use of these or other corrosive products can damage your sunglasses and may void the warranty. 

Over exposure to salt from sweat or salt water can also damage your sunglasses and will void the warranty. Salt is corrosive and can cause delamination, flaking, distortion and other types of damage to the S4 sunglass lens and frame. If your sunglasses are exposed to sweat or salt water you must rinse them in fresh water to prevent prolonged exposure to salt.