Custom Polarized Clip on Sunglasses for Oakley Jackknife 4.0 51X19(No Frame) Black Hand crafted workmanship on clip on lenses, virtually unbreakable Metal Clip mechanism 100%UV and full polarized protection from harmful sunlight. Convenient one hand application to Prescription frames with positive indexing lens position New leg profile to fit frames of different materials. Lens Length(mm):51, Bridge Length(mm):19. Ultra lightweight, avoid extra pressure on your nose;Scratch and Impact Resistance