PRX818XLFW 18" Class-D Active Subwoofer with WiFi 1500WThe PRX818XLFW extended low frequency subwoofer was designed and engineered to provide sub bass frequencies with accuracy and power. Used as a single sub in a sub sat system or in multiples as part of a scalable, large format sound reinforcement system, the PRX818XLFW performs with exceptional efficiency and control. The subs are stackable and light weight ensuring quick set ups and tear downs. And due to their rugged construction are perfect for AV