EarthQuake Sound was making things shake for about 30 years(In cars that is). These were made here in the USA(San Francisco to be exact). This Old Skool 15" Rigid cone. rubber surround, vented pole piece, cast aluminum frame subwoofer has a good weight to it. Single 2.75" Voice Coil and has 4 ohms impedance(D.C.R. is 3.3 on my Fluke meter). If I'm not mistaken, this is a 90's model. Removed from the cab it was in. You are more than welcome to come check it out. Two7nine two2four Four3four Three.