But not water proof. There is a difference between the two. Since the MR60B lives near the water almost all the time, all of the major components such as the spider, surround etc. have been specially coated to have the protection that they need from corrosion that is present in a humid and salty environment.
Polyurethane is a resilient, flexible, and durable manufactured material that can take the place of paint, cotton, rubber, metal, or wood in thousands of applications across virtually all fields. It can be hard like fiberglass, squishy like upholstery foam, protective like varnish, bouncy like rubber, or sticky like glue. In the specific case of our cones, this material allows for maximum flexibility that produces great sounding speakers lasting you a long, long time.
For a modern edge, the best car speaker could be the high tech Mylar tweeter, as it generally has more ability for a wider variance of sound modifications and channel handling. Unlike paper cones, the Mylar has a higher rate of durability, as the cone is made of a plastic poly material, which does not rip or tare easily, under abnormal frequency changes.
Rubber is a synthetic material valued for its chemical inertness, impermeability to air, and the ability to endure or resist exposure to the many types of weather fronts. Rubber has applications from Sports equipment to automotive parts, the medical industry, and more. We use them for the Surrounds that connect the cone to the basket. Did you know that most modern chewing gum uses food-grade rubber as the central gum base, which contributes not only the gum's elasticity but an obstinate, sticky quality? Just like that chewing gum, the Rubber Surround in our speakers can take the equivalent amount of abuse without quitting on you.
One of the most abundant elements on earth, Aluminum is remarkable for its low density and for its ability to resist corrosion. It is nonmagnetic and does not easily ignite. This solid material has the ability to perform under stress in both high tension and high compression environments. Aluminum is relatively soft, making one of the more ideal materials to use in voice coils.