The Fossil 3100 Sunglasses deliver classic rectangle styling in a durable acetate frame that's built for everyday wear. Available in black with gray-blue lenses and gray with green lenses, these full-rim frames feature a two-tone design—the front in matte black or gray contrasts with glossy blue or gray temples—plus subtle metal accents at the hinges that add a refined touch without the weight. Acetate Construction for Comfort and Flexibility Acetate is a plant-derived material that's hypoallergenic, lightweight, and flexible. The 3100's acetate construction won't irritate sensitive skin, and the material adapts slightly to your face over time for a custom fit. Fossil's flexible spring hinges reduce pressure behind the ears and help the frames hold their shape through daily use. At 53mm lens width, 18mm bridge, and 140mm temples, the fit suits most medium to large faces. Rectangle frames like these work especially well for round face shapes—the angular lines add definition and balance softer features. Prescription-Ready and UV Protected These frames accept prescription lenses, so you can add single-vision, progressive, or bifocal lenses through your optician or our lens service. The included lenses provide UV protection for bright-day wear. Fossil has built a reputation for affordable quality since 1984, and the 3100 fits that tradition—straightforward styling, solid materials, and a price that doesn't require a second thought if you need a reliable daily pair.