Surf Ears 4.0 Ear PlugsEnhanced durability and a new wingless design The core of SurfEars 4. 0 is made with 91% post consumer recycled plastic including material taken up from from the ocean. Designed for minimal impact, SurfEars 4. 0 storage case is partly made with repurposed silicone rubber. Introducing our new Fused Core & Mesh, weve completely re engineered the foundation of SurfEars 4. 0. While retaining full acoustic performance, this upgrade improves toughness and