Eminence Delta Pro 18C Speakers
Eminence Delta Pro 18C 18" sub-bass driver is a high power 18" pro audio subwoofer speaker with cast aluminium frame, a large 67 oz. ferrite magnet structure, a 2.5" high power voice coil, and is a very efficient speaker at 96 db/spl with 1 watt input.
Rated for 1,000 watts program power handling by Eminence, the Delta Pro 18C is optimized for very small vented subwoofer systems. One of the nicest general purpose high output 4 ohm 18" speakers out there - it has a sturdy cast frame, it takes tons of power, is very efficient, offers smooth frequency response with low distortion.
Full specs here: http://www.eminence.com/speakers/speaker-detail/?model=Delta_Pro_18C