Tjuettan

Hello everyone! I recently bought a subwoofer second hand from Klipsch, but I did not receive the power cable as well. It seems to be an old brand from Klipsch since I can´t find the model on their website and the cable output is very strange, I have been to various electronic shops and Hi-Fi shops and no one have seen this output before. Just wanted to know if any of you knows which cable I need and where I can find it. Pictures below. Cheers!