The useful decision with the Ballast M is fit. At 128.6 mm wide with a 15 mm bridge, it lands in a medium footprint, with 60 mm lenses and a 125 mm temple length. It’s a frameless Costa sunglass for water sports and other outdoor use, with Premium Polarized 580 lenses and 100% UV protection. The lenses are scratch resistant and meant to hold up to daily wear. The TR90 nylon frame keeps weight down at 16 grams, which suits anglers who want a light pair that doesn’t feel bulky through a long day. Lens options change tint and mirror, not sizing.
