View larger Water Resistant This product is water resistant but not waterproof. Since the MR752C 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. Specifications 7.5 inch 2-way Marine speakersPeak power: 400 WattsRMS power: 200Impedance: 4 OhmsFrequency response: 40Hz – 20kHzSensitivity: 92 dB @ 1 W/1 MeterMounting depth: 2-3/4” (70mm) View larger Cone – Poly Injection Polyurethane, categorized as a polymer, 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. View larger Tweeter – Mylar Dome Mylar is the brand name for a special type of stretched polyester film/plastic sheet manufactured in a range of different styles, finishes, and thicknesses. Generally, the dome tweeter is a step up from the semi-dome tweeter, primarily because of improved sound dispersion. The dome shape radiates sound with a wider dispersion pattern than the semi-dome design. Since high-frequency sound waves are very directional, a wider dispersion of the sound waves will give you a larger "sweet spot" to work with when setting up your system. View larger Surround – Butyl Rubber Butyl Rubber is a synthetic (man made) substance and is valued for its chemical inertness, impermeability to air, and the ability to endure or resist exposure to many types of weather fronts. Butyl 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 butyl 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 Butyl Rubber Surround in our speakers can take the equivalent amount of abuse without quitting on you. View larger Rear Of MR752C View larger Voice Coil – Aluminum Our speakers are capable of higher or elevated temperature strength and fatigue properties that will increase performance and efficiency of heavy duty play time through lower weight and higher operating temperatures.