Rockville RTB80A 8" 400 Watt Powered Subwoofer Bass Tube + MP3 Input Rockville RTB80A 8 400w Powered Subwoofer Bass Tube. 400 Watts Peak/200 Watts RMS. 8 High power woofer in vented tubular enclosure. Integrated, built-in 250 Watts RMS Rated amplifier. Rear aero vent bass system. Speaker level and RCA line-level input. Frequency response: 30Hz-200Hz. Sensitivity: 105 dB. Adjustable bass crossover. Molded steel woofer grill. Four steel mounting brackets + two canvas straps with Velcro fasteners. Tube is covered in durable aviation grade tweed with embroidered logo. Dimensions: 8.75 x 19