19.0mm X-Max by 70% BL method one-way (38.0mm peak to peak);Thick black anodized aluminum voice coil formers for maximum strength and heat dissipation;High efficiency air-flow management integrated into the motor for maximum voice coil cooling;Dual Aluminum Faraday rings for reduced inductance and inductive distortion (pole cap and magnet ID);Two-Year Warranty against defects in materials and workmanship