Solution 25 A1 - The perfect solution for an active installation!3-Channel active amplifier1 x Channel used for built in sub2 x Channels spare for front speaker active installationAux input on Bass Remote for external Audio InputBass-reflex subwoofer enclosure, flared vent reducing air noise, built-in bi-amping: one 300W subwoofer amp and two 100W amps for kit amplification, using the 25 A1 subwoofer, numerous controls available.The ultimate solution combining flexibility and easy-install while offering 500W self-contained amplification capacity.