OMNITRONIC PAS-181 MK4 is a passive 18-inch bassreflex subwoofer designed for low-frequency reinforcement in professional PA applications. It contains one 18-inch woofer with a ferrite magnet, an aluminum basket, a cardboard/paper cone, and a 4-inch low-frequency voice coil. The enclosure provides 700 W RMS power handling, a 37–200 Hz frequency range, 129 dB maximum SPL, and an 8-ohm impedance. It features two recessed handles, an M20 flange, optional wheels, and a black textured plywood cabinet.