Dayton Audio ND105-4 4" Aluminum Cone Midbass Neo Driver 4 Ohm Extended-range 60 Hz to 10 kHz performance Rubber-edged aluminum alloy cone Large excursion capability-4 mm Xmax, 20 mm peak Self-shielded Neo-Balanced motor structure 1&quot; 4-layer underhung voice coil with polyimide former