Superior Dual PTD™ Pure-Titanium Domes offset at 30° angles. Outdoor high-frequency performance is smooth, pure, exceptionally well-extended with tremendous clarity across a wide outdoor listening area. No other rock speaker on the market can compare! Superior Dual Voice-Coil ICP™ Injection-Molded Co-Polymer Polypropylene Cones. Die-cast aluminum chassis, oversized, computer-optimized ferrite magnets, superior motor structures. Midrange performance is superbly detailed and oh, so natural. Unparalleled Outdoor Quality! PolyGlass™ Enclosures with Faux-Stone Finishes are fully sealed (no ports!) and highly damped. Stainless steel grilles and self-draining natural rock fissures. Weather, water and UV-resistant, even under adverse conditions.