What pioneer component used a speaker with a chord

Hello ladies and gents I need some help identifying a component. I found a pair of pioneer speakers at a flea market with a " power chord" attached to the back. On the end of the chord it has a plug not outlet that goes???. Also when I opened the back it reads Pioneer CS-18S and there appears to be an Amplifier inside. I am not a tech but it looks like a powered crossover? I would appreciate any information you may have