From the seller:

Professionally maintained and teched prior to shipment. The 12XT active/passive cabinet is the mid sized model of the L-ACOUSTICS® XT coaxial series and has an operating frequency bandwidth of 55 Hz to 20 kHz. This response can be lowered to 32 Hz with the addition of the SB18 subwoofer. The 12XT enclosure contains a 3’’ diaphragm compression driver coaxially loaded by a 12’’ low frequency transducer mounted in a bass-reflex tuned enclosure. In passive configuration, the 12XT onboard crossover network uses proprietary third order filters. The linearization and protection of the transducers is defined by the drive parameters contained in the amplified controllers.  **Priced individually, sold in pairs in dual case.