A jetty is placed usually at a mouth of an inlet to protect the shoreline from erosion from currents. It also creates an amazing reef for fishing and diving. Protect your eyes and enjoy the cool features of these awesome glasses! The lens width is 59mm, bridge width 15mm, and arm length 144mm. 100% UV protection. 1.0mm Triacetate (TAC) polarized lenses. Fade-resistant, rimless lens frame. Integrated hinge will stand up to repeated use. Authentic Calcutta logo.