JBL Stadium 1224 subwoofer 12" (300 mm).

JBL Stadium 1224 (STADIUM series) subwoofer 12" (300 mm).

SSI™ (Selectable Smart Impedance)
Stadium subwoofers feature an exclusive dual impedance switch that lets you choose either load impedance option. This allows for a variety of system configurations when using one subwoofer or multiples. Not available from any other manufacturer, SSI lets you reconfigure your system by simply flipping a switch.
Aero-cooled voice coil
The Stadium’s voice coil significantly increases power handling and improves reliability by going with the flow—of air. The woofer’s motor channels air pumped by the cone movement past the voice coil, and the voice coil former exposes the coil’s inner and outer surfaces to the airflow. This aero-cooling design is unique among aftermarket subwoofers.