Positive pressure comfort with wide angle styling. Ergonomic shape fits the facial bone structure. Designed for fitness swimmers, the B-300 offers comfort and a stylish, streamlined look with flat CR-39 or polycarbonate fog resistant lenses. Very popular with triathletes. Recommended for: fitness open water swimmers, and seniors. CR-39 optically correct plastic for best visual clarity. More scratch resistant than polycarbonate.