Product Info SIZE: M (131MM) Oakley®’s HSTN Metal showcases the original frame’s progressive design and heritage features of the first generation of HSTN while being in a league of its own. The original frame came to life after Oakley’s team of designers worked closely with friends of the brand in search of the next fresh take on lifestyle eyewear. The resulting sunglass with striking modernized circular lenses has now been evolved a step further with a wire trigger design. This special design pays homage to Eyeshade by replicating its unique aesthetic, originally created with a goggle lens and wire coat hanger. HSTN Metal also features Unobtainium® nosepads for the first time, providing unparalleled comfort and improved grip, while the BiO-Matter®* frame material gives the frame all-day durability. *BiO-Matter is made from bio-materials having at least 56% bio-based carbon content (representing ratio of castor oil to fossil sources) ? DESIGN - Fresh take on a classic shape in a progressive design inspired by cultural undercurrents and with a nod to our heritage ? FRAME MATERIAL - Lightweight and durable BiO-Matter® frame provides all-day comfort ? NOD TO THE PAST - Modernized metal trigger stem design inspired by Oakley's iconic Razor Blade and made from metal in homage to the original Eyeshade prototype ? NO-SLIP GRIP: Unobtainium® nosepads provide no-slip grip when wet to help increase retention ? SEE MORE DETAILS - Available with Prizm™ Lens Technology designed to enhance color and contrast so you can see more detail ? PRESCRIPTION READY - Available with Oakley Authentic Prescription lenses that come laser etched with the ellipse logo on left wearing lens for proof of Oakley authenticity. IMPACT PROTECTION Oakley lenses are designed and tested under extreme high mass and high velocity circumstances to ensure uncompromising protection across a wide range of demanding conditions. SIZE & FIT Our Sizing Frames are measured in millimeters. We’ve included this information for each of our frames to help you estimate how they’ll fit your face. FRAME & LENSES Size: M (131mm) 1Lens Height 48 mm 2Frame Width 131.3 mm 3Arm Length 137 mm 4Lens Width 52 mm 5Bridge Width 21 mm Measurements listed intended for customer use only. Not intended to be used by opticians to fill prescriptions. Fit Options Regular: A medium lens front designed for those who prefer to cover an average portion of the face. High Bridge Fit: Offers a more secure and comfortable fit for those with a high nose bridge and lower cheekbones. A good choice if the bridge of your nose is above the level of your pupils.