Phase Linear Aliante SI 12'' hi-end subwoofer drivers Hand made in Italy 19-300 Hz 4 Ohm 400 watt RMS 900 peak power 10mm thick aluminum honeycomb sandwiched between layers of fiberglass and Kevlar to form a flat piston cone. One way, with heat resistant 5'' voice coil for great durability submerged in ferrofluid. Perfect working condition. Cosmetically near mint From Japan and not used here.