Inspired by the United States Bullion Depository in Fort Knox, Kentucky, these high quality, form-fitting sunglasses make for a comfortable and flexible fit. Best on larger head shapes, the Glossy Black and Tortoise Shell Fade Fort Knocks Rx offer a timeless silhouette—perfect for your next pair of prescription sunglasses. Glossy black and tortoise shell fade frames Gold hardware Spring hinges Single vision or progressive Lenses available in a variety of colors All sunglasses lenses are polarized Digital lens technology offers sharper image quality and enhanced contrast Correction available in -6 to +3* Astigmatism correction available to -4.00 Pupillary distance available in 57-80mm** Scratch resistant coating Anti-reflective coating FDA compliant impact-resistant polycarbonate lenses UV400 protection Lightweight Unisex Hard shell case and microfiber pouch included Prescription eyewear is available for U.S. customers only *Correction available may vary per prescription and frame style selection. Our technicians will verify your eligibility before your order goes to production and will contact you with any issues. **Some PD restrictions may apply on specific frames. A large disparity between customer PD and frame PD will increase thickness of final product.