FBT Vertus CLA 208SA Processed Active Subwoofer 600W RMS, 129dB SPL. The FBT CLA-208SA is a 2 x 8” active subwoofer in bass-reflex design and birch ply enclosure. The internal Class D amplifier delivers 600W and is matched with a switch mode power supply and a DSP processor with filtering functions, equalization and speaker protection. Created with the idea of extending the FBT Vertus CLA608A’s low frequency performance in live applications, the CLA208SA serves as the base support for the CLA604A column speaker which can either be frontally mounted to the sub, as well as fixed upon the optional stand through the M20 socket on the upside of the sub. The Vertus CLA208SA subwoofers are modular as well, and they can be stacked to enlarge and increase the maximum SPL.