Pioneer TS-A250D4 10" Dual 4 ohms Voice Coil Sub-woofer. Frequency Range = 20 Hertz to 2 kilohertz. Maximum Peak Power Handling = 1300 Watts. Continuous Power Handling (RMS) = 400 Watts. Pioneer TS-A250D4 10 Dual 4 ohms voice coil subwoofer 10" Glass fiber and mica interlaced injection molded polypropylene (IMPP) cone construction Butyl rubber surround and aramid Fiber spider for strength and linearity during high excursion Oversized 56 oz Double stacked magnet and vented pole yoke for increased power handling Pioneer A-series sound design purposely matches the subwoofer and full-range Loudspeakers to provide seamless and smooth sound characteristics