The FX20-PRO is a horn-loaded subwoofer with an Electro-Voice EVX180B 18" high-performance loudspeaker. For optimum dynamics, power amp outputs up to 1200 W @ 8 Ohm are recommended. The efficiency of the speaker is 101 dB/1W/1m, the maximum sound pressure level is 135 dB. The loudspeaker is protected against overheating by the Voice Coil Tracking protection circuit. Depending on the application, crossover frequencies between 80 Hz and 140 Hz are recommended. Das The case is made of 15 mm birch plywood and covered with a very resistant textured lacquer. The front grill is made of powder-coated steel. 4 castors and 4 ergonomically designed handles for easy handling.