- Unique performance-to-size ratio - High power 130dB continuous, 136dB peak - Fitted with integral handles and castors - Direct radiating, long excursion 21” driver - Integrated 35mm pole adapter The KL21ma is a high performance powered sub-bass system designed for use with small to medium wavefront systems, in both touring and install applications. The KL21ma includes a powered and DSP processed powered output channel, designed for KR400S ultra slim satellite or KL21 passive 21” subwoofer.