The KEF KASA500 is a subwoofer amplifier specifically designed to work with KEF in-wall subwoofers (Ci3160RLb-THX and Ci4100QLb). 
 
KASA500 is a powerful Class-D Dual 250WPC amplifier. This DSP controlled system amplifier is optimized to deliver thunderous bass from KEF Ci subwoofers. With both line and speaker level inputs, and DSP configurable pass-through with optional high pass filters – the KASA500 is versatile and can be deployed in limitless system configurations. Optional rack mount ears included.