The Elevation Series ELS212t (touring - flyable) and ELS212i (installation - not flyable) Subwoofers are dual 12", 4 ohm, 1600-watt subwoofers with long excursion neodymium woofers capable of achieving 134db SPL down to 40Hz at -3db. Using an innovative new technology developed by Tom Danley called a Tapped Horn design (patent pending), the Tapped Horn maximizes driver efficiency by allowing radiation from the rear of the driver to enter the system at a tap, located further down the horn flare towards the mouth.